Aflatoxin exposure, malaria and hepatitis B infection in rural Gambian children.

Aflatoxin-albumin adduct levels were measured in serum samples obtained from a group of Gambian children. The relationships between exposure to aflatoxin and the prevalence of malaria, between exposure and humoral and cellular responses in vitro to defined malaria antigens and, amongst children with evidence of exposure to hepatitis B infection, between aflatoxin and carriage of the hepatitis B surface antigen (HBsAg), were assessed. Aflatoxin-albumin adduct was found in nearly all serum samples collected during a survey performed at the end of the dry season and levels of adduct were generally high (up to 720 pg aflatoxin-lysine equivalent/mg albumin). Higher levels of aflatoxin-albumin adduct were detected in Wollof children than in children of other ethnic groups and marked variation in mean adduct levels between villages was observed. Aflatoxin-albumin adduct levels were higher in children who were HbsAg positive and in children with Plasmodium falciparum parasitaemia than in controls. However, levels of adduct had no consistent effect on either malaria-specific antibody responses, lymphoproliferative responses in vitro, or morbidity from malaria during the subsequent rainy season. Much lower levels of aflatoxin-albumin adduct were detected in repeat samples obtained at the end of the rainy season. There was poor correlation between dry and rainy season levels of adduct in individual children. We have shown that Gambian children are exposed to high levels of aflatoxin. The seasonal variation of aflatoxin-albumin adduct and marked fluctuation of adduct with time in individual children need to be considered in the future planning of epidemiological studies using this marker of exposure.(ABSTRACT TRUNCATED AT 250 WORDS)     

Penetration and enrichment of flufenamic acid in calf skin from patients with stasis dermatitis

To investigate the hypothesis that the application of medicaments to skin from the lower leg of patients with stasis dermatitis might lead to their enhanced enrichment, compared with uninvolved skin from the same region, a penetration study was performed with flufenamic acid. In 5 patients with pronounced changes of chronic venous insufficiency and in 5 control patients without chronic venous insufficiency the flufenamic acid content in skin sections parallel to the surface was determined by HPLC. In chronic venous insufficiency-skin, the flufenamic acid concentration was higher in all skin levels compared to control skin. This enrichment of the substance could lead to a prolonged and more intense contact with antigen-presenting cells in this region, thus promoting the development of contact allergies observed so frequently in this pathologic condition.     

Spatial summation of the differential light threshold as a function of visual field location and age

Static differential light thresholds were measured as a function of stimulus size (Goldmann sizes I-V) along four visual field meridia (75, 165, 255 and 345°) with the Humphrey Field Analyzer 640. Data were obtained for both young ( n = 10, age 23.6 ± 2.9 years) and elderly ( n = 10. age 72.0 ± 5.2 years) normal subjects. The resulting peripheral spatial summation curves could be equated to the foveal data simply by a change in size scale, which increased linearly with eccentricity. E₂, values, expressing the eccentricity at which stimulus size must double for performance to remain comparable to the fovea, were in the order of 3–9°. Whilst the rate of scale change is approximately the same for both young and elderly observers, differences in performance can be explained by a combination of lower sensitivity and a bias in sensitivity towards larger stimulus sizes with increasing age.     

Accumulation of O6- and 7-methylguanine in DNA of N-nitroso-N-methylbenzylamine-treated rats is restricted to non-target organs for N-nitroso-N-methylbenzylamine-induced carcinogenesis.

The distribution and accumulation of O6-methylguanine (O6-meGua) and 7-methylguanine (7-meGua) was investigated immunocytochemically in target and non-target tissues of rats injected twice weekly with 0.5 mg N-nitroso-N-methylbenzylamine (NMBzA)/kg for 16.5 weeks. Seventy two hours after every two or three doses, two NMBzA-treated rats and one control rat were killed. Tissue-specific cell proliferation was investigated after two injections of bromodeoxyuridine (BrdU) to rats unexposed to NMBzA. Neither O6-meGua- nor 7-meGua-specific immunostaining could be observed in the target tissues for tumor induction, i.e. esophagus, tongue and forestomach. Accumulation of both O6-meGua and 7-meGua was found, however, in nasal, tracheal and bronchiolar epithelia and glands--tissues for which tumor induction by NMBzA has not been reported. An explanation for this phenomenon might be the relatively low levels of cellular proliferation we observed in the latter epithelia. The present results support the hypothesis that the tumorigenic organotropism of NMBzA is determined both by the level of DNA methylation and the proliferative capacity of the methylated cells.     

Autoantibodies associated with endometriosis: can their detection predict presence of the disease?

To evaluate the usefulness of autoantibody detection as a nonoperative method of diagnosing endometriosis, we tested 221 sera from 215 patients from the infertility, gynecology, and gynecologic oncology services by an indirect immunofluorescence assay using monolayer cultures of an endometrial carcinoma cell line. The assay showed positive cytoplasmic staining, demonstrating a sensitivity of 83% in the patients with laparoscopically confirmed endometriosis. The specificity of the assay was 65% for the infertility patients and 76% for the infertility and gynecology patients combined. Several gynecologic cancer patients showed either nuclear or nuclear and cytoplasmic staining, but few showed exclusive cytoplasmic staining. These initial results suggest that detection of antibodies might be useful for the diagnosis of endometriosis.     

Respiratory symptoms,ventilatory impairment,and bronchial reactivity in oil mist-exposed automobile workers

Studies concerning the respiratory effects of oil mists are sparse and contradictory. The aim of this study was to determine the respective effects of occupational exposure to straight cutting oils and soluble mineral oils on the prevalence of respiratory symptoms, ventilatory impairment, and bronchial reactivity. The population study consisted of 308 male workers of a large French car-making plant, including 40 subjects chronically exposed to straight cutting oils (group S), 51 subjects chronically exposed to soluble mineral oils (group E), 139 subjects with chronic dual exposure to straight cutting oils and soluble mineral oils (group D), and 78 unexposed assembly workers used as a control group (group C). Worker evaluation included a standardized questionnaire, measurement of pulmonary function, and a methacholine challenge. Oil mist concentration at the work place was determined by gravimetric analysis. The arithmetic mean concentration was 2.6 ± 1.8 mg/m³. The geometric mean concentration was 2.2 pm 1.9 mg/m³. The prevalence of respiratory symptoms did not differ significantly among the four groups. However, the subjects exposed to straight cutting oils (group S + group D) had a significantly higher prevalence of chronic cough and/or phlegm than the others (group E + group O): 25.7% vs. 16.3% (p = 0.048). Furthermore, the prevalence of cough and/or phlegm increased significantly (p = 0.03) with increasing duration of exposure to straight cutting oils after adjustment on smoking categories. Lung function tests did not differ significantly among the four groups but we observed a significant decrease of forced expiratory volume in 1 see (FEV₁), forced expiratory flow during the middle half of forced vital capacity (FEF_25-75), and maximal flow rate at 50% and 25% of exhaled forced vital capacity (V₅₀ and V₂₅) according to duration of exposure among smokers exposed to straight cutting oils, suggesting a synergistic effect of tobacco and insoluble oils. No effect of exposure to mineral oils on bronchial reactivity was demonstrated. It is concluded that despite low levels of pollution by oil mists, the present study has shown tenuous adverse chronic effects of straight cutting oils on respiratory symptoms and lung function. However, no adverse effect of soluble mineral oils was demonstrated. These results suggest that threshold limit values for mineral oils should be reassessed.     

Spatial summation and the cortical magnification of perimetric profiles

M-scaling of the conventional spot targets of clinical perimetry at low photopic adaptation levels, such as that of the Octopus automated perimeter, does not result in the expected isosensitive profile using the current equations for humans. This disparity has been attributed to variations in the ganglion cell characteristics across the retina, most notably that of spatial summation. The hypothesis was further investigated by M-scaling the perimetric sensitivity recorded under conditions favouring reduced spatial summation, namely an increased adaptation level and a longer stimulus duration afforded by the Humphrey Field Analyzer. The M-scaled data exhibited a paracentral reduction in sensitivity relative to the theoretical isosensitive profile and an increased sensitivity beyond an eccentricity of 12 degrees. This indicates that for perimetric spot stimuli, the current human M-scaling equations under represent the fovea at the visual cortex. The implications for the design of perimetric routines are discussed.     

Fowlpox virus recombinant encoding the measles virus fusion protein: protection of mice against fatal measles encephalitis

A recombinant Fowlpox virus engineered to encode the measles virus fusion protein was shown to protect mice against a challenge measles infection. A vaccine dose of about 10(6) p.f.u. was needed to protect nearly 100% of the animals. Mice failed to develop a significant level of antibodies directed against measles virus suggesting that other components of the immune system may be involved.     

Microsurgical management of the lumbar intervertebral disc-disease

One hundred consecutive patients operated on for sciatica pain using microsurgical techniques between April 1984 and February 1985 were evaluated retrospectively. This paper gives preoperative clinical data, end-result of surgery, rate of complications and true recurrent herniations.On the basis of the results, both soon after operation and at later follow-up (between three and five years) we fell encouraged to continue using this mode of operation. Complete or significant pain relief was achieved in 92% of patients; 93% were able to return to their preoperative normal physical activities. The frequency of complications was low.