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Biomedical subjects

J Neve

Publications and source records attributed to J Neve.

At least 19 recordsLinked to original sources
PubMed2004

Serum selenium and cancer mortality: a nested case-control study within an age- and sex-stratified sample of the Belgian adult population.

OBJECTIVE: To study the predictive power of serum selenium with regard to cancer mortality in a large sample of the Belgian population given the lack of coherence in the results of observational epidemiological studies in this domain. DESIGN: A prospective case-control study within a stratified sample of the Belgian male and female population. SUBJECTS: A total of 201 cases randomly selected from all cancer deaths (N=343) during a 10-y mortality follow-up of a large age- and sex-stratified sample of the total Belgian population aged 25-74 y were matched for age and gender with 603 controls. STATISTICS: Conditional logistic regression for both univariate and multivariate analyses using tertile distribution of serum selenium in controls. Odds ratios (ORs) are adjusted for 10 baseline characteristics. RESULTS: Unadjusted ORs of cancer deaths taking the highest tertile of serum selenium as a reference: in male subjects T1/T3 is 2.2 (CI 1.3-3.7) (P for trend 0.011), whereas in female subjects a nonsignificant OR of 0.8 is observed. In multivariate analyses, no significant modifications of the ORs are observed for the predictive relation of serum selenium with cancer mortality. Besides serum selenium, beta-carotene intake and smoking are independent predictors in male subjects. CONCLUSIONS: In this nested case-control study of a stratified sample from the Belgian population, serum selenium is an independent predictor of cancer mortality in male subjects only, in a country with rather high serum selenium levels with respect to most other European countries.

Adult↗
PubMed2004

The reactions of oxicam and sulfoanilide non steroidal anti-inflammatory drugs with hypochlorous acid: determination of the rate constants with an assay based on the competition with para-aminobenzoic acid chlorination and identification of some oxidation products.

Hypochlorous acid (HOCl) is an oxygen-derived species involved in physiological processes related to the defence of the organism that may cause adverse effects when its production is insufficiently controlled. In order to examine its reactivity with potential scavenging molecules from the non steroidal anti-inflammatory drugs (NSAIDs) family, a competition assay based on para-aminobenzoic acid (PABA) chlorination was developed. The original optimised in vitro fluorimetric procedure offered the possibility to determine rate constants (ks) for the reaction with HOCl in physiologically relevant conditions. The specificity of the system was improved by a liquid chromatography (LC) which allows the separation of the drugs and their oxidation products. After determination of the rate constant for PABA chlorination by HOCl (mean +/- SD in M(-1) s(-1): 4.3 +/- 0.3 x 10(3)), the applied mathematical model for a chemical competition permits to obtain linear curves from competition studies between several NSAIDs and PABA. Their slopes provided the following rate constants for the different studied drugs: tenoxicam: 4.0 +/- 0.7 x 10(3), piroxicam: 3.6 +/- 0.7 x 10(3), lornoxicam: 4.3 +/- 0.7 x 10(3), meloxicam: 1.7 +/- 0.3 x 10(4), nimesulide: 2.3 +/- 0.6 x 10(2). Meloxicam therefore reacted significantly faster than the other oxicams and nimesulide, which is the weakest scavenger of the studied series. The identification of some of the oxidation products by NMR or MS permitted to explore the reaction mechanism and to examine some aspects of the structure/activity relationships for the molecules of the same chemical family.

4-Aminobenzoic Acid↗
PubMed2001

Selenium, iodine and fungal contamination in Yulin District (People's Republic of China) endemic for Kashin-Beck disease.

We studied the status of selenium, iodine and fungal contamination in 353 school children (age 5-14 years) from four rural villages in the District of Yulin. In three villages Kashin-Beck disease (KBD) was endemic, whereas there were no cases of KBD in the fourth village. Clinical, biological and radiological examinations (right hand) were performed and KBD was established by X-ray diagnosis. The prevalence rate of KBD was 30.2%, 44.2% and 45.3% in the three endemic villages. Mean hair selenium and urine iodine concentrations were lower in affected than in unaffected children and fungal contamination in cereal grains stored in families with KBD was more elevated than in families without KBD. Low hair selenium concentration and presence of fungal cereal contamination were significantly associated with an increased risk of KBD, but low urine iodine was not.

Adolescent↗
PubMed2001

Zinc supplementation increases bone alkaline phosphatase in healthy men.

Zinc takes part in the metabolism of bone as a constituent of the matrix and as an activator of several metallo-enzymes. Animal in vitro and in vivo studies strongly suggest that zinc supplementation could stimulate bone formation and inhibit bone resorption but data in humans remain rare. The biological effects of 50 mg zinc given orally as gluconate in 20 healthy male volunteers were investigated in a 12 weeks double-blind placebo-controlled randomized trial. To investigate bone turnover, total alkaline phosphatases activity (ALP), bone specific alkaline phosphatase activity (BAPE) and BAP mass (BAP-M) concentration were measured as parameters of bone formation while urine calcium and C-terminal collagen peptide were determined as parameters of bone resorption. Samples were obtained in fasting subjects at baseline and after 6 and 12 weeks. In zinc treated subjects, a significant increase was observed at least after 12 weeks in total ALP (p < 0.01), BAP-M (p < 0.05) and BAP-E (p < 0.02). These parameters did not significantly change in the placebo group. Urine zinc/creatinine ratio significantly increased after 6 (p < 0.03) and 12 weeks (p < 0.04) in the zinc-treated group and was significantly different from the placebo group (p < 0.002). There was no significant effect of zinc supplementation on parameters of bone resorption. In conclusion, zinc supplementation at supraphysiological doses increased parameters of bone formation in healthy men while parameters of bone resorption remained unchanged.

Adult↗
PubMed2000

Temporal relationship between immune cell influx and the expression of inducible nitric oxide synthase, interleukin-4 and interferon-gamma in pancreatic islets of NOD mice following adoptive transfer of diabetic spleen cells.

Beta cell destruction in NOD mice can be accelerated by adoptive transfer of diabetic spleen cells into irradiated adult NOD mice. Here mice receiving diabetic spleen cells were examined at days 0, 7, 14, 21 and at onset of diabetes for the resulting insulitis and the number of intra-islet CD4 and CD8 cells and macrophages. The progression of insulitis and the number of intra-islet CD4 and CD8 cells and macrophages were correlated with the expression and co-localization of inducible nitric oxide synthase, interferon-gamma and interleukin-4 by dual-label light and confocal immunofluorescence microscopy. Diabetes developed in 7/8 mice by 27 days following cell transfer. The insulitis score increased slightly by day 7 but rose sharply at day 14 (p = 0.001) and was maintained until diabetes. The mean number of intra-islet CD4 and CD8 cells and macrophages showed a similar trend to the insulitis scores and were present in almost equal numbers within the islets. Immunolabelling for inducible nitric oxide synthase was observed at day 7 in only some cells of a few islets but increased sharply from day 14. It was restricted to islets with insulitis and was co-localized in selective macrophages. Weak intra-islet interleukin-4 labelling was observed at days 7 and 14 but became more pronounced at day 21 and at onset of diabetes, being present in selective CD4 cells. Intra-islet labelling for interferon-gamma was first observed at day 21, but became more intense at onset of diabetes and was co-localized in a proportion of macrophages. Both cytokines were expressed in islets with advanced insulitis. Interferon-gamma staining was also observed within endothelial cells located in the exocrine pancreas. We conclude that transfer of diabetic spleen cells results in a rapid influx of CD4 and CD8 cells and macrophages within the pancreas of recipient mice. During the period of heightened insulitis, selective immune cells begin to express inducible nitric oxide synthase and the opposing cytokines, interferon-gamma and interleukin-4. Expression of these molecules becomes more pronounced immediately prior to and during the onset of diabetes.

Adoptive Transfer↗
PubMed1999

Sideroxylonal C, a new inhibitor of human plasminogen activator inhibitor type-1, from the flowers of Eucalyptus albens.

Sideroxylonal C (3), a new phloroglucinol dimer, was isolated from the flowers of Eucalyptus albens through bioassay-guided fractionation. The structure elucidation was based on 1D and 2D NMR experiments, MS analysis, and comparison with sideroxylonals A (1) and B (2). Sideroxylonal C inhibited human plasminogen activator inhibitor type-1 at 4.7 microM without any significant effect on human tissue plasminogen activator.

Benzofurans↗
PubMed1999

[Kashin-Beck disease in China: osteochondrodysplasia related to nutrition and environment].

Kashin-Beck disease is a endemic juvenile osteochondrodysplasy, whose association with selenium deficiency and/or mycotoxin toxicity has been corroborated by epidemiological studies in China, including Tibet. Iodine deficiency appears to be a new etiological factor. Together with the geographical and epidemiological exploration of the disease, scientific multidisciplinary investigations (clinics, radiological imaging, histology, environmental and molecular biology) should afford to understand the cause of the disease before it disappears as a consequence of the evolution of the Chinese Society, including in Tibet.

Adult↗
PubMed1998

Trace element deficiency and toxicity.

Trace elements are involved in enzymatic activities, immunological reactions, physiological mechanisms and carcinogenesis. Deficiency in some trace elements, such as iron and iodine, is still an important health problem, especially in developing countries. Some groups of individuals are more likely to develop trace element deficiency. The role of trace elements deficiency is suspected in various clinical situations and is now confirmed by well designed supplementation studies. Although toxicity of trace elements with clinical manifestations is rare, it has been observed that manganese toxicity may occur in patients receiving parenteral nutrition. Recent data about trace elements deficiency and toxicity are indicated in this review.

Adolescent↗
PubMed1997

Forward-masked intensity discrimination: duration effects and spectral effects.

Three experiments were completed to examine the effect of masker duration and spectrum on forward-masked intensity discrimination. Four listeners participated in each experiment. Intensity discrimination was measured in quiet and in the presence of forward maskers using adaptive forced-choice procedures. The standard duration was either short (10 ms) or long (250 ms) in experiment 1 and short (10 ms) in experiment 2. The standard always occurred 100 ms after the offset of the masker. In the first experiment employing 1.0-kHz maskers and standards, a short duration masker (10 ms) produced more masking than a long duration masker (250 ms). A mid-level elevation of the Weber fraction was observed for all conditions. To ensure that the results of experiment 1 were not influenced by off-frequency listening, the second experiment employed a broadband noise masker. As before, a short duration (10 ms) masker produced more masking than a long duration masker (100 ms) and a mid-level elevation of Weber fractions was observed. This outcome is inconsistent with a peripheral sensory effect for which an increase in masker duration should result in a greater amount of adaptation, and, as a consequence more masking. A third experiment employing a broadband noise masker and standard showed the greatest amount of masking for low-level standards, but only when the duration of the masker and standard was short. This result is similar to one seen for a single listener in the first experiment for short duration tonal maskers and standards. For this listener, a second tone presented at 4.133 kHz presented simultaneously with the 1.0 kHz masker reduced significantly the amount of masking for low-level standards, but the mid-level elevation of the Weber fraction remained. Taken together, these results suggest that perceptual similarity plays a role in forward-masked intensity discrimination but does not account entirely for the mid-level elevation of the Weber fraction.

Adult↗
PubMed1996

Deficiency in antioxidant factors in patients with alcohol-related chronic pancreatitis.

Free radicals have been suspected to play a role in the pathogenicity of alcohol-related chronic pancreatitis. The aim of this study was to determine the status of several antioxidant parameters in these patients and examine the factors that are likely to influence them. Thirty-five subjects (23 males and 12 females, mean age 48 +/- 8 years) with disease proven by endoscopic pancreatography and 14 healthy controls (6 males and 8 females, mean age 44 +/- 7 years) were included in the study. Biochemical antioxidant parameters included: selenium, zinc, and copper levels in plasma; glutathione peroxidase in plasma and erythrocytes; plasma malondialdehyde concentrations assessed by thiobarbituric acid reactants; and serum vitamin E and A levels. Selenium and vitamin E oral intake was assessed by a five-day diet analysis. Hemoglobin (130 +/- 16 vs 143 +/- 15 g/liter), vitamin E (8 +/- 5 vs 16 +/- 9 mg/liter), vitamin A (30 +/- 11 vs 49 +/- 12 micrograms/dl), selenium (54 +/- 20 vs 87 +/- 11 micrograms/liter), and plasma glutathione peroxidase (903 +/- 313 vs 1326 +/- 168 units/liter) were significantly lower in patients than in controls (P < 0.05). In contrast, white blood cell count, C-reactive protein, and plasma copper levels were significantly higher in patients than in controls. Cholesterol, triglycerides, iron, ferritin, total proteins, zinc, and malondialdehyde were not different. Vitamin E was lower in patients with steatorrhea, while vitamin A was lower in patients with concomitant diabetes mellitus. Dietary intakes were not different between patients and controls. In conclusion, patients with alcohol-related chronic pancreatitis have low blood levels in many antioxidant factors. Dietary intakes of some of them (selenium and vitamin E) are adequate, however. Such deficiencies are secondary to pancreatic insufficiency and probably to increased requirements related to enhanced oxidative stress.

Adult↗
PubMed1996

Reference values for serum selenium in various areas-evaluated according to the TRACY protocol.

Published reports on selenium concentrations in serum and plasma were critically reviewed according to the criteria set up by the expert group of the international project TRACY. The aim was to examine both pre-analytical (sampling conditions and characteristics of the group) and analytical factors described in papers to establish reference values for evaluation of persons with deficiency or excessive exposure to the element. Out of 291 papers published during the period 1983 to 1993, which we reviewed, 36 were considered suitable for the TRACY project. In order to eliminate sources of variation due to age and health status, only data concerning healthy adults were retained. Of the sampling and other pre-analytical factors, geographical area and time of sampling were found to be of high importance. Gender, occupation, diet data and use of supplements or medications were also considered important determinants, but ethnic origin, smoking and fasting, contamination control and storage of sample were held to be of relatively low importance. Concerning analytical factors, accuracy criteria were generally satisfied although not extensively documented. Reference materials for serum selenium, which contribute to better analytical reliability have been available for over 10 years. Due to the geographical variation of selenium intake, one universal reference serum selenium value for the world's population was not feasible but the data selected allowed documentation of the serum selenium concentration levels among populations of different areas, mostly in Europe. Critical use of the published TRACY criteria in future papers will certainly extend their reliability and scientific significance.

Adult↗
PubMed1995

Precision and accuracy of in vivo bone mineral measurement in rats using dual-energy X-ray absorptiometry.

The aim of this study was to evaluate the precision and accuracy of dual-energy X-ray absorptiometry (DXA) for measuring bone mineral content at different sites of the skeleton in rats. In vitro the reproducibility error was very small (< 1%), but in vivo the intra-observer variability ranged from 0.9% to 6.0%. Several factors have been shown to affect in vivo reproducibility: the reproducibility was better when the results were expressed as bone mineral density (BMD) rather than bone mineral content (BMC), intra-observer variability was better than the inter-observer variability, and a higher error was observed for the tibia compared with that for vertebrae and femur. The accuracy of measurement at the femur and tibia was assessed by comparing the values with ash weight and with biochemically determined calcium content. The correlation coefficients (R) between the in vitro BMC and the dry weight or the calcium content were higher than 0.99 for both the femur and the tibia. SEE ranged between 0.0 g (ash weight) and 2.0 mg (Ca content). Using in vitro BMC, ash weight could be estimated with an accuracy error close to 0 and calcium content with an error ranging between 0.82% and 6.80%. The R values obtained between the in vivo and in vitro BMC were 0.98 and 0.97 respectively for femur and tibia, with SEE of 0.04 and 0.02 g respectively. In conclusion, the in vivo precision of the technique was found to be too low. To be of practical use it is important in the design of experimentation to try to reduce the measurement error.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorptiometry, Photon↗
PubMed1995

Linear and non linear competition plots in the deoxyribose assay for determination of rate constants for reaction of nonsteroidal antiinflammatory drugs with hydroxyl radicals.

Performing the deoxyribose (DR) assay for determination of the rate constants for reaction of non steroidal antiinflammatory drugs with hydroxyl radicals led to some unusual competition plots. The molecules from the arylpropionic family of drugs: ibuprofen, flurbiprofen, ketoprofen and naproxen produced the linear relationship. However, acemetacin, diclofenac Na, flufenamic acid, indometacin, indometacin, niflumic acid, tolmetin Na and sulindac presented non linear competition plots manifesting at relatively low drug concentrations. This effect was corrected by increasing DR concentrations from 2.8 mM to 15 mM. The modification did not affect rate constants values for those derivatives which already presented a linear plot at 2.8 mM, but allowed to calculate rate constants for other compounds. It is suggested that the experimental conditions have to be adapted particularly for those derivatives with a relatively high rate constant for reaction with the radical species. The oxicam derivatives (tenoxicam and piroxicam) presented another kind of deviation that revealed a prooxidant effect in this system: non linear plots were also observed at relatively low drug concentrations, but in the opposite direction than for the other molecules. This last effect was independent of DR concentration but could be corrected by increasing ascorbate concentration in the system.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1993

Plasma and liver selenium levels in the rat during supplementation with 0.5, 2, 6, and 15 ppm selenium in drinking water.

Plasma and liver selenium of Wistar rats were determined after 1, 3, and 6 mo supplementation with 0.5, 2, 6, or 15 ppm selenium as sodium selenite in drinking water. Plasma selenium was not different from control values at additional intake of 0.5 ppm but increased above usual levels at higher intakes. A highly significant correlation was observed between the total quantity of selenium ingested and plasma selenium after 1 mo treatment (r = 0.99, p < 0.01), but was less pronounced after 3 and 6 mo (0.94, p < 0.05, and 0.78, p < 0.05, respectively). The decrease in plasma selenium with time of treatment was more pronounced at higher intakes. There was also a highly significant correlation between total selenium intake and liver selenium concentration (r = 0.99, p < 0.01) after 1 mo of treatment, but this time liver selenium did not change with time, and the correlation remained highly significant throughout the investigation. Liver selenium therefore appears as a more sensitive and more representative measure of selenium intake than plasma selenium. Most supplements did not affect body weight and survival of animals, except when the diet was supplemented with 15 ppm for 6 mo; however, alterations in biochemical parameters concerning lipid status and hepatic function were observed at levels above 2.0 ppm.

Animals↗
PubMed1991

Effects of chronic prednisolone administration on plasma copper in rats with adjuvant arthritis.

Copper metabolism is known to be significantly affected by inflammation or by glucocorticoid administration. We have previously demonstrated that acute prednisolone administration induces a moderate but sustained increase in plasma copper in healthy rats while it induces a more pronounced but shorter increase in rats with adjuvant arthritis. In the present study we have investigated the effects of chronic prednisolone administration (around 0.65 mg/kg daily in food) in both healthy rats and rats with adjuvant arthritis at various stages of the disease. In healthy rats, a slight but significant increase of 11% was observed in plasma copper after 3 weeks of treatment. This modification was no longer apparent after 5 weeks of treatment. In arthritic rats, plasma copper was, as expected, higher than in healthy rats and reached a maximum 3 weeks after adjuvant injection. In prednisolone-treated arthritic rats, there was a sustained decrease in plasma copper starting after 2 weeks of treatment which could be correlated with an improvement of the clinical and biochemical signs of inflammation. In conclusion, chronic prednisolone treatment only slightly increases plasma copper in healthy rats while in arthritic rats plasma copper is dependent on the severity of the disease which is improved by the treatment.

Administration, Oral↗
PubMed1990

[Selenium and pregnancy].

Selenium is an essential trace element with protective properties against endogenous or exogenous aggression, mainly due to the hyperproduction of oxygen derivatives. During pregnancy, a depletion in plasma selenium occurs regulated by hormones from the placenta. Selenium requirement is simultaneously increased which is partly satisfied by the increased retention of the element resulting from a decrease in selenium urinary excretion. The foetus accumulates selenium at the end of pregnancy by storing it in the liver. However, after birth, selenium stores rapidly deplete. Selenium deficiency is apparently not responsible for pregnancy or delivery problems in man. However, the infant is exposed to pronounced deficiency symptoms or to the worsening of some diseases liable to affect the young baby, particularly if premature because the usual selenium dietary intake is marginal in this country, selenium supplementation with 25 to 50 micrograms selenium per day is advisable and should be considered among other trace elements as a food supplement for pregnant and lactating woman.

Female↗
PubMed1989

Effects of chronic and acute corticosteroid therapy on zinc and copper status in rheumatoid arthritis patients.

The modifications in plasma, erythrocyte and urine zinc and copper concentrations induced by chronic or acute corticotherapy were studied in patients suffering from rheumatoid arthritis and the results compared with those from controls. Patients not treated with corticosteroids had low plasma zinc and high plasma copper, which significantly correlated with inflammatory parameters (erythrocyte sedimentation rate and C-reactive protein); no change was observed in erythrocyte and urine zinc and copper. Oral long-term treatment with corticosteroids (less than 10 mg prednisolone/day) was associated with a further decrease in plasma zinc only in patients with moderate inflammation. Changes induced by such a treatment were less intense than those due to severe inflammation. The administration of intravenous high doses (1 g methylprednisolone/day) resulted in a rapid decrease in plasma zinc with a return to baseline levels two days after withdrawal. The modification was associated with a sustained increase in urine zinc and copper without changes in diuresis.

Administration, Oral↗