A proof of concept study establishing Necator americanus in Crohn's patients and reservoir donors.
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Adult↗
Biomedical subjects
D Pritchard
Publications and source records attributed to D Pritchard.
Energy and nutrient recovery from sewage sludge via pyrolysis.
Energy recovery and nutrient reuse from sewage sludge has traditionally been achieved via anaerobic digestion/power generation with land application of the biosolids. By contrast, thermal processes such as pyrolysis have typically been used only for energy recovery. One such technology has demonstrated at commercial scale that all of the energy in sludge can be beneficially recovered and reused. No attempt was however made to recover and reuse sludge nutrients. There are many potential benefits of using pyrolysis for both energy and nutrient recovery. Firstly, unlike digestion, the principal energy product is oil, which can readily be stored and used when required, ensuring that energy recovery is maximised. Secondly is that the sludge nutrients are recovered in the pyrolysis char. Laboratory soil incubation studies using char from the Subiaco demonstration plant were conducted over an eight-week period to confirm nutrient availability. Results from this study showed that the phosphorus in the char is plant available although the nitrogen was insoluble. Based on these results it appears that there is potential to use pyrolysis as an effective means to recover and reuse both the energy and the very valuable phosphorus present in sewage sludges.
Agriculture↗
Independent effects of intestinal parasite infection and domestic allergen exposure on risk of wheeze in Ethiopia: a nested case-control study.
BACKGROUND: Why asthma is rare in rural subsistence societies is not clear. We tested the hypotheses that the risk of asthma is reduced by intestinal parasites or hepatitis A infection, and increased by exposure to dust-mite allergen or organophosphorus insecticides in urban and rural areas of Jimma, Ethiopia. METHODS: From 12876 individuals who took part in a study of asthma and atopy in urban and rural Jimma in 1996, we identified all who reported wheeze in the previous 12 months, and a random subsample of controls. In 1999, we assessed parasites in faecal samples, Der p 1 levels in bedding, hepatitis A antibodies, serum cholinesterase (a marker of organophosphorus exposure), total and specific serum IgE, and skin sensitisation to Dermatophagoides pteronyssinus in 205 cases and 399 controls aged over 16 years. The effects of parasitosis, Der p 1 level, hepatitis A seropositivity, and cholinesterase concentration on risk of wheeze, and the role of IgE and skin sensitisation in these associations, were analysed by multiple logistic regression. FINDINGS: The risk of wheeze was independently reduced by hookworm infection by an odds ratio of 0.48 (95% CI 0.24-0.93, p=0.03), increased in relation to Der p 1 level (odds ratio per quartile 1.26 [1.00-1.59], p=0.05), and was unrelated to hepatitis A seropositivity or cholinesterase concentration. In the urban population, D pteronyssinus skin sensitisation was more strongly related to wheeze (9.45 [5.03-17.75]) than in the rural areas (1.95 [0.58-6.61], p for interaction=0.017), where D pteronyssinus sensitisation was common, but unrelated to wheeze in the presence of high-intensity parasite infection. INTERPRETATION: High degrees of parasite infection might prevent asthma symptoms in atopic individuals.
Adolescent↗
Identification of a collagen-binding protein from Necator americanus by using a cDNA-expression phage display library.
A phage display library was made starting from a cDNA library from the hematophagous human parasite Necator americanus. The cDNA library was transferred by polymerase chain reaction (PCR) cloning into phage display vectors (phagemids), using specially designed primers such that proteins would be expressed as fusions with the C-terminal part of the phage coat protein pVI. The vectors used are multicloning site variants of the original pDONG vectors described by Jespers et al. (1995). Electroporation of the ligation mixtures into electrocompetent Escherichia coli TGI cells yielded 3 x 10(8) pG6A, 1.9 x 10(8) pG6B, and 1 x 10(8) pG6C transfectants for N. americanus. The final libraries consisted of a mix of equal numbers of insert-containing phages from the A, B, and C libraries. Selection of phages for binding to human collagen was performed. Four rounds of panning on human collagens I and III resulted in a significant enrichment of collagen-binding phages from the N. americanus libraries. PCR analysis revealed various insert lengths; however, sequence determination indicated that all phages contained the same protein, albeit with different poly-A tail lengths. The encoded protein itself is a 135-amino acid protein (15 kDa), with no apparent homology to any other known protein. Next the protein was recloned into E. coli using the pET-15b-vector. Upon isopropyl-1-thio-beta-D-galactopyranoside induction, the recombinant protein, rNecH1, could be recovered by urea treatment from inclusion bodies. The rNecH1 protein binds to different collagens: human I > rat I > human III = calf skin I in a specific, dose-dependent, and saturable manner.
Amino Acid Sequence↗
Radiation Therapy Oncology Group. Research Plan 2002-2006. Sarcoma Committee.
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Forecasting↗
Anger, depression, and coping interactions in headache activity and adjustment: a controlled study.
OBJECTIVE: To determine if individuals in the general community with chronic headache or migraine differ in terms of anger, depression, and coping strategies and from headache-free individuals in terms of anger and depression. METHOD: A community sample comprising 16 chronic tension-type headache (CTH), 28 migraine headache (MH), and 38 headache-free control subjects (CNT) were compared on measures of anger, depression, and use of various coping strategies. Affective and coping measures, recorded during a headache-free period, were regressed on headache activity measured in a daily diary over the following 2 weeks. Relationships between anger, depression, and coping were also examined in each of the headache groups. RESULTS: The MH subjects were found to use less effective coping strategies than controls and CTH, while the CTH group had higher levels on depression and various anger scales compared to controls and MH. Direct positive relationships were observed between suppressed anger and depression in the MH group, and between trait anger and depression in the CTH group. Anger and coping were predictive of headache activity in the following 2 weeks for both MH and CTH groups, while depression and coping, compared to coping only, were predictive of lifestyle interference from head pain in MH and CTH, respectively. CONCLUSION: The results support a relationship between affective and coping factors in headache activity and adjustment.
Adaptation, Psychological↗
Total and specific IgE (house dust mite and intestinal helminths) in asthmatics and controls from Gondar, Ethiopia.
BACKGROUND: The role, if any, of parasitosis in the development of asthma remains incompletely understood; both 'protective' and 'predictive' associations have been reported. We report a study which examined immunoglobulin (Ig) E responses to two common helminths in asthmatics living in Ethiopia. OBJECTIVE: To compare the frequencies of specific IgE antibodies to Ascaris and Necator species and to Der p 1 among 84 adult asthmatics and a referent group of nonasthmatics. METHODS: A case-control analysis. RESULTS: Total IgE levels were not different between the two groups. The presence of specific IgE to Der p 1 was strongly associated with asthma (P = 0.001). Raised levels of Ascaris-(P = 0.010) and Necator- (P = 0.001) specific IgE antibodies were more common among referents; there were no associations between specific IgE production to Der p 1 and either of the two parasites. CONCLUSION: These findings confirm the association between Der p 1 sensitization and asthma among urban, adult Ethiopians. While they also indicate a negative relationship with two indicators of helminth infestation it appears that this is not mediated through the immunological response to common aeroallergens.
Adolescent↗
The human hookworm pathogen Necator americanus induces apoptosis in T lymphocytes.
In the present study, we demonstrate that Jurkat T cells undergo apoptosis when cocultured with the human hook-worm Necator americanus. Pro-apoptotic activity was dose-dependent and readily detectable in hookworm secretions. This pro-apoptotic effect appears to be specific to cells of T lineage since the monocytic cell line, THP-1, the erythroleukaemic cell line, K562, and the basophil cell line, KU812, were unaffected. The induction of apoptosis in Jurkat T cells by the hookworm secretions did not involve cell activation or the Fas/Fas ligand interaction. In addition, the pro-apoptotic effect of the hookworm, or its secretions, was observed with activated human T cells but not with resting peripheral blood lymphocytes. These findings support the hypothesis that the hookworms' ability to recurrently infect humans is due to the parasite creating a site of 'immune privilege' around itself. This strategy promptly induces any reactive host leucocytes infiltrating the site of parasite colonization to undergo apoptosis, which reduces inflammation and renders the infection relatively asymptomatic.
Animals↗
Positron emission tomography in imaging spinal cord tumors.
The ability of positron emission tomography (PET) to detect spinal cord tumors was studied prospectively in 14 patients presenting over a 5-year period. Abnormal uptake by [18F]-fluorodeoxyglucose (FDG) or 11C-methionine was detected in all except one. These data were assessed in relation to magnetic resonance imaging (MRI) findings with regard to tumor type and extent preoperatively, findings at operation, and subsequent clinical course. The group consisted of six astrocytomas, five ependymomas, one mixed ependymoma and astrocytoma, one schwannoma, and one ganglioglioma, all confirmed histologically. This is the largest study comparing spinal PET to MRI. Accurate preoperative correlation between PET and MRI was found in all eight patients scanned at first presentation. The PET uptake was in keeping with the low-grade histology of the tumors. Postoperatively, PET and MRI findings were in agreement in nine patients. In eight of these the findings were in keeping with the subsequent clinical course. In three patients, however, the PET findings were at variance with the clinical course and MRI findings. In one, persistent FDG uptake after radiotherapy was seen where there was subsequent tumor resolution. In two patients with low-grade astrocytomas, scanned with FDG and 11C-methionine, respectively, tracer was not taken up by residual tumor. In this small group of patients, PET did not provide additional useful information. This could be because all tumors studied were low grade and the limited spatial resolution of PET does not lend itself to imaging small spinal cord tumors. The prospective study of larger numbers of patients with a wider range of tumor types is required, but this might be difficult to achieve given the rarity of spinal cord tumors.
Adolescent↗
Was Charlemagne killed by his tablecloth?
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Asbestos↗
Time-series analyses of general arousal and headache activity in the natural environment.
A naturalistic longitudinal study was conducted to examine temporal relationships between subjective dimensions of general arousal and headache activity. The "tense arousal" dimension of Thayer's biopsychological model of mood and arousal (The Biopsychology of Mood and Arousal. New York: Oxford University Press; 1989) was recorded using the Activation-Deactivation Adjective Check List (ADACL). Recordings were made eight times daily, every 2 hours from awakening, in conjunction with a clinical diary recording head pain intensity and duration. Three time series of daily, half-daily, and bihourly headache and tension scores were modeled and cross-correlated. Results indicated moderate positive same-time correlations, but revealed large interindividual and intraindividual variation in temporal relationships.
Adult↗
Tobacco consumption among Swaziland high-school students and their parents and teachers.
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Adolescent↗
Evidence for the upregulation of osteogenic protein-1 mRNA expression in musculoskeletal neoplasms.
Little is known about bone and cartilage tumors at the molecular level; thus, the identification of genes associated with these tumors may be useful as markers and therapeutic targets. To address this issue and to test the hypothesis that abnormal expression of one or more growth factors in the transforming growth factor-beta superfamily is associated with musculoskeletal neoplasia, degenerate primers based on the conserved sequences in these genes were made for screening tumor samples by reverse transcription-polymerase chain reaction. First, these primers were used to obtain a comparative profile between a low-grade chondrosarcoma and its dedifferentiated high-grade counterpart in the same patient. This experiment identified an amplified DNA product in the high-grade sample that was identical to osteogenic protein-1/bone morphogenetic protein-7. Osteogenic protein-1 mRNA expression was 17-fold greater in this high-grade sample than in the low-grade one. Osteogenic protein-1 was highly expressed (three of three) in human osteosarcoma cell lines but was not expressed (zero of four) in normal osteoblast samples. Screening for gene expression of osteogenic protein-1 in 57 osteosarcomas and chondrosarcomas indicated that 44% (range: 38-52%) of them were positive for osteogenic protein-1 mRNA. Screening of breast and prostate tumors revealed a similar association with osteogenic protein-1 mRNA expression.
Bone Morphogenetic Protein 7↗
Relationships between arousal-related moods and episodic tension-type headache: a biopsychological study.
An exploratory study was conducted examining arousal-related moods and episodic tension-type headache. Twelve subjects meeting International Headache Society criteria for episodic tension-type headache and 12 headache-free controls recorded headache activity and mood eight times daily for 14 consecutive days. Moods were measured using the Activation-Deactivation Adjective Check List, a self-report list that subjectively represents general arousal along two dimensions of Tension and Energy. Headache subjects had higher Tension levels than controls even in the absence of pain, and greater variation in this dimension as well. Within the headache group, Tension during pain-free periods was significantly lower than when experiencing headache, and was correlated with headache activity. The results were taken to support Thayer's (1989) biopsychological model of mood and arousal, and are discussed in terms of the model's heuristic value for general arousal and headache research.
Adult↗
IORT in the management of extremity and limb girdle soft tissue sarcomas.
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Adolescent↗
Metabolism of 2,3,5,6-tetrachloronitrobenzene (tecnazene) in rat.
1. The metabolic fate of [U-14C]-2,3,5,6-tetrachloronitrobenzene (tecnazene) has been determined in the male and female rat following a single dose of 1 mg/kg and in surgically prepared, bile-duct-cannulated rats following a single oral dose of 135 mg/kg. 2. Radioactivity in the female rat was excreted mainly in urine (82%). The male rat, however, excreted approximately equal amounts of radioactivity in urine and faeces (the latter via bile). 3. The principal metabolic pathway was conjugation with glutathione (GSH) and concomitant nitro-displacement. The GSH-conjugate and related metabolites were excreted in the bile and ultimately in the urine as the mercapturic acid conjugate. The cysteine conjugate underwent beta-lyase-mediated metabolism to yield a thiol that underwent subsequent methylation to the thioanisole followed by S-oxidation. 4. A novel tetrachloromethyldisulphide metabolite was also formed.
Animals↗
The incorporation of radiolabelled sulphur from captan into protein and its impact on a DNA binding study.
Repeated administration of high doses of captan is known to produce tumours specifically in the duodenum of mice. Captan is not carcinogenic in the rat. In this study, DNA purified from the liver, stomach, duodenum and jejenum of mice dosed with 35S radiolabelled captan was found to contain radioactivity equivalent to Covalent Binding Indices in the range 38-91; that from the bone marrow had a CBI of 2.8. The distribution of radioactivity between the various tissues did not reflect the target organ specificity of captan. Attempts to further purify the DNA samples using caesium chloride gradients resulted in partial separation of the radioactivity from the DNA suggesting that covalent binding to the DNA may not have occurred. A study of the chemical breakdown of captan showed that captan is unstable, producing a variety of potentially reactive species containing sulphur. Evidence was further obtained to show that the sulphur of captan is incorporated into endogenous amino acids and protein. Hepatic DNA from mice dosed with 35S radiolabelled N-acetylcysteine, and two thiazolidine derivatives which are analogous to known metabolites of captan, was radiolabelled to a similar extent to that from captan treated mice. Furthermore, the DNA from each of these treatments had similar properties on caesium chloride gradients. It was concluded that the radioactivity associated with DNA in the captan DNA binding study was present in the low levels of protein which are always associated with purified DNA samples.
Acetylcysteine↗
EMG levels in children who suffer from severe headache.
Very little information exists about the physiology of pediatric headache and in particular, the role that skeletal musculature plays in the genesis of head pain. This study explored EMG levels in the neck and forehead in a group of 12 children who complained of severe headache. Comparisons were made with a matched group of 12 children who were headache-free. Results suggested that children with headache suffer from very tense neck muscles which may reflect high levels of anxiety.
Adolescent↗