Development of a µ-TPC detector as a standard instrument for low-energy neutron field characterisation.

In order to measure the energy and fluence of neutron fields, in the energy range of 8 to 1 MeV, a new primary standard is being developed at the Institute for Radioprotection and Nuclear Safety (IRSN). This project, Micro Time Projection Chamber (µ-TPC), carried out in collaboration with the Laboratoire de Physqique Subatomique et de Cosmologie (LPSC), is based on the nucleus recoil detector principle. The measurement strategy requires track reconstruction of recoiling nuclei down to a few kiloelectronvolts, which can be achieved using a micro-pattern gaseous detector. A gas mixture, mainly isobutane, is used as an n-p converter to detect neutrons within the detection volume. Then electrons, coming from the ionisation of the gas by the proton recoil, are collected by the pixelised anode (2D projection). A self-triggered electronics system is able to perform the anode readout at a 50-MHz frequency in order to give the third dimension of the track. Then, the scattering angle is deduced from this track using algorithms. The charge collection leads to the proton energy, taking into account the ionisation quenching factor. This article emphasises the neutron energy measurements of a monoenergetic neutron field produced at 127 keV. The fluence measurement is not shown in this article. The measurements are compared with Monte Carlo simulations using realistic neutron fields and simulations of the detector response. The discrepancy between experiments and simulations is 5 keV mainly due to the calibration uncertainties of 10 %.

GATE: a simulation toolkit for PET and SPECT.

Monte Carlo simulation is an essential tool in emission tomography that can assist in the design of new medical imaging devices, the optimization of acquisition protocols and the development or assessment of image reconstruction algorithms and correction techniques. GATE, the Geant4 Application for Tomographic Emission, encapsulates the Geant4 libraries to achieve a modular, versatile, scripted simulation toolkit adapted to the field of nuclear medicine. In particular, GATE allows the description of time-dependent phenomena such as source or detector movement, and source decay kinetics. This feature makes it possible to simulate time curves under realistic acquisition conditions and to test dynamic reconstruction algorithms. This paper gives a detailed description of the design and development of GATE by the OpenGATE collaboration, whose continuing objective is to improve, document and validate GATE by simulating commercially available imaging systems for PET and SPECT. Large effort is also invested in the ability and the flexibility to model novel detection systems or systems still under design. A public release of GATE licensed under the GNU Lesser General Public License can be downloaded at http:/www-lphe.epfl.ch/GATE/. Two benchmarks developed for PET and SPECT to test the installation of GATE and to serve as a tutorial for the users are presented. Extensive validation of the GATE simulation platform has been started, comparing simulations and measurements on commercially available acquisition systems. References to those results are listed. The future prospects towards the gridification of GATE and its extension to other domains such as dosimetry are also discussed.

Dietary intake of Indians living in the metropolitan area of Durban.

OBJECTIVE: To report on energy and nutrient intakes, as a risk factor for coronary heart disease in Indian South Africans. DESIGN: Cross-sectional dietary study as part of a coronary heart disease survey. SETTING: Metropolitan area of Durban, South Africa. SUBJECTS: Free-living Indian men (n = 406) and women (n = 370) 15-69 years of age. METHODOLOGY: Dietary data were collected by three interviewers using a 24-h dietary recall and expressed as median intakes of macronutrients. RESULTS: Results reported a low energy intake and the percentage of energy derived from total fat varied between 32.3 and 34.9% in men and between 33.1 and 36.1% in women. The energy intake to basal metabolic rate (EI:BMR) ratios were low for all age groups suggesting potential under-reporting. Intake of polyunsaturated fatty acids was high, more than 10% of energy, with a median polyunsaturated to saturated fatty acid ratio (P:S ratio) that varied between 1.38 and 1.96 for the various age and sex groups. Dietary cholesterol varied between 66 and 117 mg per 4.2 MJ in men and between 76 and 109 mg per 4.2 MJ in women. Dietary fibre intakes were low and varied between 8.0 and 11.0 g per 4.2 MJ in men and between 7.6 and 9.6 g per 4.2 MJ in women. CONCLUSIONS: The dietary P: S ratios were high and the effect of such a high P:S ratio on the oxidation of low density lipoprotein in this population, with a high prevalence of coronary heart disease (CHD), should be investigated as a possible risk factor for CHD.

Risk factors leading to coronary heart disease among the black, Indian and white peoples of Durban.

This paper compares and contrasts the important risk factors which may predispose to coronary heart disease (CHD) in the Black, Indian and White peoples of Durban. CHD is very common the Whites and Indians in South Africa. In contrast CHD is still uncommon in the Blacks of South Africa. Indians living in South Africa have a higher prevalence of CHD compared to Indians in India.

[Appearance of hepatitis C virus replication and increase of aminotransferase activity after corticoid treatment of presumed autoimmune hepatitis. 2 cases]. / Apparition d'une réplication du virus de l'hépatite C et augmentation de l'activité des aminotransférases après traitement corticoïde d'une hépatite présumée auto-immune. Deux observations.

Autoimmune-related and hepatitis C virus-related chronic hepatitis are sometimes difficult to differentiate. We report two cases of chronic hepatitis with high levels of serum anti-smooth muscle antibodies, positive hepatitis C virus serology, and negative serum RNA, which were first treated with corticotherapy. Both patients responded with marked increases in aminotransferase levels, and positive RNA. The first case may have been type 1 autoimmune hepatitis with hepatitis C virus infection, and the second chronic hepatitis C with positive serum auto-antibodies. The increase in viral antigen expression on the surface of the hepatocytes following corticosteroid treatment may have favoured a direct cytopathogenic effect of hepatitis C virus.

Risk factors for coronary heart disease in the white community of Durban.

Coronary heart disease (CHD) is the leading cause of death among the white and Indian populations of Durban. This was a community-based study of the white population of Durban, which is predominantly English-speaking. There were 396 subjects (194 men, 202 women) aged 15-69 years. A history of CHD was present in 9.3% of the subjects. The important risk factors were hypercholesterolaemia, hypertension and smoking. The minor risk factors were obesity, hypertriglyceridaemia, hyperuricaemia, a sedentary occupation and a history of CHD in the immediate family. Electrocardiograph abnormalities denoting CHD were present in 17% of subjects. A study of the major risk factors showed that 35.1% (age and sex adjusted) had at least one major risk factor at the higher level (level A) and 33.8% (age and sex adjusted) at the lower risk levels (level B). When the combination of risk factors was taken into account, 15.2% and 28% had two major risk factors, one each at levels A and B respectively. On average the percentage of men and women with one risk factor or more increased with age. A protective high-density lipoprotein/total cholesterol ratio > or = 20% was present in 53.5% of the respondents. Because of the severe nature of CHD, an intensive programme for the primary prevention of CHD risk factors should be instituted.

Study of risk factors leading to coronary heart disease in urban Zulus.

Coronary heart disease (CHD) is still relatively uncommon in the black population of South Africa. We embarked on a study to determine the prevalence of risk factors leading to CHD in the black population of Durban. The study sample was selected from patients attending a dental clinic at a hospital. A total of 458 Zulus (age range 16-69 years) were studied. The prevalence of CHD was 2.4%. The prevalence percentage of selected risk factors were: hypertension (SBP > or = 140 mmHg and/or a DBP > or = 90 mmHg) was 28%, males 31.9%, females 25.4%; protective levels of high density lipoprotein cholesterol/total cholesterol (HDLC/TC) (> or = 20%) were 81.3%; diabetes, males 4.9%, females 2.9%; smoking > or = ten cigarettes per day, males 28.1%, females 3.4%; obesity, males 3.7%, females 22.6%. We have found the Minnesota Coding System for ECG changes of CHD and Rose questionnaire to be unreliable for eliciting CHD in Blacks. Hypercholesterolaemia is less common and this may explain the low incidence of CHD in Blacks. Epidemics of CHD as seen in the Indian, 'mixed' and white South Africans can still be prevented in the black population but preventive measures must be instituted rapidly.

Risk factors and coronary heart disease in Durban blacks--the missing links.

Coronary heart disease (CHD) is still relatively uncommon in the black population of South Africa. We embarked on a study to determine the prevalence of risk factors leading to CHD in the black population of Durban. The study sample was selected from patients attending a dental clinic at a hospital. A total of 458 patients (age range 16-69 years) was studied. The prevalence of CHD was 2.4%. The percentage prevalences of selected risk factors were: hypertension (blood pressure > or = 140 mmHg systolic and/or > or = 90 mmHg diastolic) 28% (31.9% for males, 25.4% for females); protective levels of high-density lipoprotein/total cholesterol > or = 20%, 81.3%; diabetes mellitus 4.9% for males, 2.9% for females; smoking > or = 10 cigarettes per day 28.1% for males, 3.4% for females; obesity 3.7% for males 22.6% for females. We found the Minnesota Coding System for electrocardiographic changes of CHD and the Rose questionnaire to be unreliable for eliciting CHD in blacks. Hypercholesterolaemia is less common, and this may explain the low incidence of CHD in blacks. Epidemics of CHD as seen in Indian, coloured and white South Africans can still be prevented in the black population, but preventive measures must be instituted rapidly.

The effect of disinfectants on perforated gloves.

Three types of gloves, 'Biogel', 'Regent Dispo Surgical' gloves and Ansell gammex were perforated, and contaminated with Escherichia coli or Pseudomonas aeruginosa as test organisms applied either to the hand or the glove surface. The glove surface was decontaminated with alcoholic chlorhexidine ('Hibisol'), methylated spirit, or soap and water. The experiments were performed in triplicate on three separate days. The experiments were designed to study the ability of the three disinfection methods to reduce the bacterial count of 10(6) colony forming units (cfu) ml-1 (applied to perforated gloves or hands) sufficiently to permit the re-use of such gloves for non-sterile ward procedures. The best method of disinfection was using alcoholic chlorhexidine which not only reduced glove surface carriage but also reduced transfer of bacteria to the hands through the perforation in the gloves. Soap and water was the least effective. Escherichia coli was more easily removed than P. aeruginosa. We recommend that non-sterile ward procedures may be carried out even after gloves have been perforated provided alcoholic chlorhexidine is used between each procedure to reduce cross-infection between patients.

Ascorbic acid prevents the dose-dependent inhibitory effects of polyphenols and phytates on nonheme-iron absorption.

The effects of maize-bran phytate and of a polyphenol (tannic acid) on iron absorption from a white-bread meal were tested in 199 subjects. The phytate content was varied by adding different concentrations of phytate-free and ordinary maize bran. Iron absorption decreased progressively when maize bran containing increasing amounts of phytate phosphorous (phytate P) (from 10 to 58 mg) was given. The inhibitory effect was overcome by 30 mg ascorbic acid. The inhibitory effects of tannic acid (from 12 to 55 mg) were also dose dependent. Studies suggested that greater than or equal to 50 mg ascorbic acid would be required to overcome the inhibitory effects on iron absorption of any meal containing greater than 100 mg tannic acid. Our findings indicate that it may be possible to predict the bioavailability of iron in a diet if due account is taken of the relative content in the diet of the major promoters and inhibitors of iron absorption.

Risk factors for coronary heart disease in the Indians of Durban.

Coronary heart disease (CHD) is a major problem in migrant Indians throughout the world. In South Africa it has reached 'epidemic' proportions. A field survey was conducted among Indians in the metropolitan area of Durban to determine the prevalence and known risk factors for CHD. In a study of 778 subjects aged 15-69 years (408 men), 15.3% (sex and age adjusted 13.4%) had a history of CHD. The important risk factors in men were hypercholesterolaemia, hypertriglyceridaemia, diabetes, and smoking, and in women diabetes, hypercholesterolaemia, and hypertriglyceridaemia. The minor risk factors were hyperuricaemia, sedentary occupation, obesity in women and a positive family history of CHD. A study of the major risk factors leading to CHD showed that 52% (sex and age adjusted 45.5%) had at least one major risk factor at the higher (level A) and 68% (sex and age adjusted 61.9%) at the lower (level B) risk levels. Diabetes mellitus was strongly associated with a positive history of CHD. In 47.6% (sex and age adjusted 48.2%) of the total group resting ECG abnormalities were found that could be coded. Because of the severe nature of CHD in the migrant Indian, an immediate and intensive programme of primary prevention of CHD risk factors should be instituted.

The promotive effect of soy sauce on iron absorption in human subjects.

The effects on iron absorption of a traditionally fermented Japanese soy sauce added to soy and rice meals were assessed. The addition of soy sauce to a soy flour meal could not overcome the strong inhibition of iron absorption (geometric mean absorption 7.2 per cent with soy sauce vs. 8.7 per cent without, P = 0.5). However, soy sauce added to a rice meal instead of soy flour significantly improved the geometric mean iron absorption (13.9 per cent with soy sauce vs. 5.2 per cent with soy flour, P = 0.002) and had a promotory effect on absorption from a rice meal alone (11.4 per cent with soy sauce vs. 3.5 per cent without, P = 0.0002). Although soy sauce contains appreciable amounts of organic acids, the addition of 340 mg lactic acid to rice did not enhance iron absorption (3.1 per cent with lactic acid vs. 2.2 per cent without, P = 0.11). The promotory effect of soy sauce on iron absorption appears to be due not only to its lack of soy protein content but may also be due to the presence of fermentation products other than organic acids.

Effect of traditional oriental soy products on iron absorption.

The effect of a variety of traditional oriental unfermented and fermented soy products on iron absorption was evaluated in 242 Indian women. When compared with a soy-flour meal containing an equal amount of protein, iron absorption was found to be significantly improved with silken tofu, natto, tempeh, rice miso, barley miso, and soybean miso. This improvement could not be adequately explained except with reference to changes in the protein composition of the products. The protein fraction profiles of the soy products were obtained by size-exclusion high-performance liquid chromatography. An inverse relationship between food iron absorption and the high-molecular-weight fraction of the soy products was demonstrated (r = 0.66, p = 0.01). However, anomalous results obtained with three products (sufu, tempeh, and fully hydrolyzed isolated soy protein) did not make it possible to reach firm conclusions concerning the effect of the protein fraction of soy on iron bioavailability.

Gastrointestinal tuberculosis in patients with pulmonary tuberculosis.

Proven or suspected intestinal tuberculosis was diagnosed in 23 (46 per cent) of 50 patients with smear-positive, cavitating pulmonary tuberculosis. The diagnosis was regarded as proven in 14 patients and suspected in the remaining nine. The frequency of proven gastrointestinal disease increased with the severity of the pulmonary tuberculosis. Small intestinal disease was encountered in only two patients. Small mucosal lesions in the caecum were the most commonly detected pathological features. Colonoscopy was of particular value in establishing the diagnosis, which could not be predicted from the patients' abdominal signs or gastrointestinal symptoms.

The microbe file.

SPIROCHAETES - 2 Other Treponemata(non-venereal syphilis) Treponema pertenue causes yaws, a chronic disease in Africa and South America. Spread: direct contact with infected lesions.