Social disparities in musculoskeletal disorders and associated mental malaise: findings from a population-based survey in France.

AIMS: Various types of musculoskeletal disorders (MSDs) have comorbid mental disorders, which may in turn have a negative influence on disease course and role impairment, but the contribution of social factors to this type of comorbidity is a much under-researched area. This study investigates whether there is a socially patterned association of MSDs with different dimensions of mental malaise. METHODS: The sample included 3,368 economically active participants aged 18-64 years, randomly selected from the Lorraine region in north-eastern France. Information was provided through a post-mailed questionnaire on fatigue, sadness/depression (Duke questionnaire) and cognitive disability during the last eight days. RESULTS: MSDs were significantly more prevalent in manual workers, clerks and other occupations than in upper and intermediate professionals, and similar occupational disparities were found for cognitive disability, fatigue and sadness/ depression. Stratifying the sample, we found the occupational disparities in cognitive disability to be much stronger among participants suffering from MSDs than among participants not suffering from MSDs, and the occupational disparities in fatigue and sadness/depression to be limited to the subsample of subjects suffering from MSDs. CONCLUSIONS: The findings demonstrate that the association of MSDs with mental malaise is much stronger in the lower occupational groups than in the higher groups. Given that psychological factors are implicated in disease prognosis and in the development of disabilities, awareness of the social dimension of the association and treatment of the comorbid mental disorders could open a promising avenue for reducing social inequalities in disability related to MSDs.

Ex vivo study of incorporation into adipocytes and lipolysis-inhibition effect of polycyclic aromatic hydrocarbons.

We have previously shown that benzo[a]pyrene (B[a]P) administrated at extremely low dose can cause weight gain in mice and that the increase in adipose tissue mass is due to inhibition of beta-adrenergic stimulation of lipolysis. Moreover we have suggested that in addition to its endocrine properties, adipose tissue act as a reservoir for many chemical carcinogens including Polycyclic Aromatic Hydrocarbons (PAHs). In this paper we show that B[a]P as well as the two C4 PAHs, pyrene and phenanthrene can bioaccumulate into adipocytes in a similar manner, but that at the difference of B[a]P, have no impact on epinephrine-induced lipolysis. On the basis of this ex vivo study, we therefore suggest that B[a]P may play a central role in carcinogenesis not only by inducing cancer through its mutagenic properties, but also by increasing the bioaccumulation capacity of the adipose tissue mass.

Beta-lactoglobulin/polysaccharide interactions during in vitro gastric and pancreatic hydrolysis assessed in dialysis bags of different molecular weight cut-offs.

The effects of gum arabic, low methylated (LM) pectin or xylan at levels of 0 and 50 wt.% on beta-lactoglobulin (beta-lg) digestibility were studied as well as the interactions between the two macromolecules during in vitro hydrolysis. The proteolysis was performed in a system involving a two-step hydrolysis: either pepsin alone, or pepsin followed by a trypsin/chymotrypsin (T/C) mixture in dialysis bags with molecular weight cut-offs (MWCO) 1000 or 8000 Da. Digestibility was estimated by the N release and by a SDS-PAGE electrophoresis of retentates from the two dialysis bags after hydrolysis. Turbidimetric measurements monitored the structural evolution of mixtures during the two-step hydrolysis. Results showed that beta-lg was almost resistant to peptic digestion and that polysaccharides increased the N release despite a reduction of pepsin activity. This is due to the formation of electrostatic complexes between polysaccharides and beta-lg, which reduced beta-lg aggregation, increasing its solubility. The polysaccharides reduced significantly the beta-lg T/C digestibility as determined using a dialysis bag with a MWCO 1000 Da, without a modification of their enzymatic activities. No significant effect of polysaccharides on the beta-lg digestibility was detected using the dialysis bag with a MWCO 8000 Da. The electrophoresis pattern did not show differences in the profile of retentates in relation with the dialysis bag used. This suggests that non-specific interactions could occur during the second step of hydrolysis between polysaccharides and amino acids or peptides smaller than 8000 Da.

Behaviour of dioxin in pig adipocytes.

Due to their lipophilic properties, dioxins can be integrated into the lipidic vacuole of adipocytes (fat cells). The aim of this study was to determine the kinetics of incorporation and release of 3H-labelled palmitic acid and 14C-labelled 2,3,7,8-TCDD in isolated adipocytes from pigs. The incorporation of 2,3,7,8-TCDD and palmitic acid was found to be concomitant under conditions of lipogenesis, under the effect of increasing quantities of insulin and in the presence of glucose. Release of these two compounds was found to be dependant on a lipolytic agent (epinephrine). These results suggest the risk of a strong increase of 2,3,7,8-TCDD, induced by lipolysis, in the blood of animals or humans previously exposed to this dioxin.

Growth hormone responses to the stimulation of hypothalamic glucoreceptors in diabetic retinopathy. Effects of catecholamine precursors and dopamine antagonists.

The effects of the stimulation of glucoreceptors located at the level of the lateral hypothalamic nuclei and sensitive to intracellular glucose deprivation on growth (GH) release are well documented in the monkey. In this study the effect of a reproducible hypoglycemic stimulatory procedure was controlled by continuously monitoring blood glucose (BG) levels in normal subjects and in a series of 120 diabetic patients. In contrast to control subjects, GH responses to similar hypoglycemic nadirs were not reproducible in diabetics (with or without diabetic retinopathy). The infusion of levodopa, precursor of both norepinephrine (NE) and dopamine, during BG decline rendered the GH response to hypoglycemia consistently reproducible. To investigate the site of action of levodopa, a group of diabetics were pretreated with a centrally active dopamine antagonist, metoclopramide hydrochloride. The pattern of GH release was similar in both groups. These data suggest that in diabetes the interaction of levodopa and adequate stimulation of hypothalamic glucoreceptor systems is mediated by an NE transmission.

Plasma glucose and insulin responses to oral glucose in nonobese subjects and patients with endogenous hypertriglyceridemia.

Plasma glucose and insulin responses to a 50-gm oral glucose challenge were determined in 396 nonobese subjects: 220 patients with endogenous hypertriglyceridemia and 176 normal persons. These groups were further subdivided on the basis of relative body weight: 1.0-1.1 and 1.1-1.2. Patients with endogenous hypertriglyceridemia whose obesity index was between 1.0 and 1.1 had significantly increased plasma glucose (more than 25%, P less than 0.001) and insulin (more than 18%, P less than 0.01) responses. Similar findings were also observed in patients with endogenous hypertriglyceridemia whose index of obesity was between 1.1 and 1.2, ie, there was a 25% increase in the plasma glucose response (P less than 0.001) and a 37% increase in the plasma insulin response (P less than 0.001). Thus, endogenous hypertriglyceridemia can occur in nonobese individuals, and these patients have an increase in their plasma glucose and insulin responses when weight-matched with nonobese normal subjects.

Increased erythrocyte aggregation in insulin-dependent diabetes mellitus and its relationship to plasma factors: a multivariate analysis.

Red blood cell aggregation in vitro (kinetics and shear resistance) was studied in 13 healthy controls and 13 type I (insulin-dependent) diabetic patients free of severe degenerative complications who were matched for age, sex, and body mass index. Measurements were performed with a device that analyzes the laser light backscattered by a blood suspension. Both the velocity of rouleau formation and the cohesion of the rouleau network were significantly increased in diabetic patients. Plasma viscosity and whole-blood viscosity measured at low shear rate (0.95 s-1) were also significantly elevated in the diabetic group. Multivariate analyses of the whole population sample and the diabetic patients confirmed the influence of plasma proteins on the kinetics of aggregation. Fibrinogen levels, which were close to normal, affected mainly the shear resistance of the aggregates. Triglyceride and apolipoprotein (apo) B levels and indexes of metabolic control or protein glycation (fasting blood glucose and fructosamine) also appeared to influence markedly both the kinetics of rouleau formation and the cohesion of the rouleau networks. These rheological abnormalities occurred in diabetic patients before the appearance of any severe degenerative complications. We suggest that these rheological abnormalities are linked to plasma or erythrocyte factors, and are not due to angiopathy.

[Study of lipid metabolic coefficient K2 in patients with hyperlipoproteinemia type IV before and after reduction of triglyceride level by adapted diet therapy]. / Etude du coefficient d'épuration lipidique K2 chez les sujets atteints d'hyperlipoprotéinémie de type IV avant et après réduction de l'hypertriglycéridémie par un traitement diététique adapté.

An intravenous fat tolerance test (IV FTT) was performed in a group of patients with type IV hyperlipoproteinemia before and after reduction of triglyceride level, the latter is obtained through a diet adapted to the nutritional sensitivity, body weight remaining constant. Before the diet the increase in cholesterol (CT) and triglycerides (TG) was related in both obese and non-obese patients to an increase in very-low-density lipoproteins (VLDL), while other lipoprotein fractions were not affected. In these patients, K2 is significantly lower than in controls whatever the nutritional sensitivity. However, K2 is lower in obese patients than in patients with normal weight, VLDL-CT and VLDL-TG are tremendously reduced by the relevant diet and K2 is constantly and significantly increased, although it does not reach a normal value in obese subjects. There is a highly significant correlation between VLDL-TG levels and K2 in obese and non-obese subjects. Several physiopathological explanations are discussed to account for the variation of K2 according to TG levels. The results obtained support the view that the K2 defect is secondary to the hyperlipoproteinemia.

Accessibility of human apolipoprotein B-100 epitopes in insulin-dependent diabetes: relation with the surface lipid environment of atherogenic particles.

The physicochemical modifications (composition and conformation) of lipoproteins containing apolipoprotein B-100 (apo B-100) were studied in normocholesterolaemic adequately controlled Type 1 insulin-dependent diabetic patients. Thirty-one normocholesterolaemic (serum cholesterol < 6.50 mmol/l) diabetic male patients and 31 age-and body mass index-adjusted healthy normolipaemic male controls were studied. Cholesterol and choline-containing phospholipids were measured in total serum and in two lipoprotein subfractions containing or not apo B (LpB and LpnoB respectively). These subfractions were separated by precipitation with concanavalin A. Total apo B-100 and two lipoprotein particles defined according to their apo B-100 epitope accessibility were determined using respectively anti-apo B polyclonal and two monoclonal antibodies that reacted with specific epitopes on the apo B molecule. Despite a classical lipid profile (cholesterol and triglyceride levels), which was quite normal in plasma from patients as compared to controls, a depletion of choline-containing phospholipid content in serum and more specifically in LpB particles was observed in diabetic patients. Decreased cholesterol content was also observed in LpB particles. Immunological analysis demonstrated an increased number of lipoprotein particles (a condition previously related to coronary artery disease) and decreased immunoaccessibility of a conformationally expressed apo B-100 epitope. These conformational changes were correlated with modifications of the surface phospholipid environment of LpB particles. It is concluded that subtle abnormalities in the composition and conformation of atherogenic apo-B-containing lipoproteins occur in Type 1 diabetes mellitus. These structural modifications may be one factor accounting for the increased rate of atherosclerosis in diabetes, despite the existence of a normal classical lipid profile.

Determination of the K2 lipid clearance coefficient by centrifugation. A comparison with the Gordis test and spectrophotometric measurement.

The K2 lipid clearance coefficient was calculated for the intravenous fat tolerance test (iv FTT), after estimating triglycerides by spectrophotometry, the Gordis technique or by preparative ultracentrifugation. The best correlation between the K2 values (r = 0.95, p < 0.001) is for the results of the Gordis test and ultracentrifugation. Spectrophotometry shows poorer correlations: r = 0.66 and p < 0.05 with the Gordis test, and r = 0.78 and p < 0.01 with ultracentrifugation. Spectrophotometry is only suitable for detection but the two other techniques can be applied to more detailed studies. Ultracentrifugation is faster, less laborious and less liable to error.

[Stability of lipid and protein composition of very low-density lipoproteins during the storage after freezing of whole serum and isolated lipoproteins (author's transl)]. / Stabilité de la composition lipidique et protéique des lipoprotéines de très basse densité au cours de la conservation après congelation du serum entier et de la lipoprotéine isolée.

The lipid and protein composition of lipoprotein is now regarded with great interest for the identification of hyperlipoproteinemias. Because this relatively time-consuming study cannot be envisaged currently in clinical services, it seems useful to analyse a storage procedure which does not affect the composition of very-low density lipoproteins, whose proportion is very important among subjects with type IV hyperlipoproteinemia. Two studies were considered, one using whole sera stored at -20 degrees C and one using very low-density lipoproteins held in the same conditions. The lipid composition was determined for triglycerides and cholesterol concentrations of total proteins, proteins soluble in tetramethylurea (apoprotein C, "arginine-rich fraction", and apoprotein D), and peptides CII, CIII1 and CIII2 of apoprotein C. For both procedures considered, no significant changes were seen in lipid and protein composition for periods as long as 8 weeks.

Comparative study of four HDL-cholesterol assay methods.

Four methods for HDL-cholesterol assay are compared using the plasma of 119 subjects. Results for the entire population and for subgroups defined by triglyceridemia and cholesterolemia levels are determined. The methods used are: ultracentrifugation, electrophoresis, dextran sulfate precipitation, and concanavalin A precipitation. The results indicate that ultracentrifugation and electrophoresis are not easily adapted to routine work, require large investments and do not separate the lipoproteins according to physiopathological criteria. The HDL values obtained with the different methods show significant differences, even though the correlations between the methods are highly significant. The precipitation methods are easiest to perform; however, the HDL-cholesterol values from dextran sulfate precipitation are higher than those from concanavalin A precipitation. The authors discuss the best choice for determining the atherogenic risks of hyperlipoproteinemia in clinical practice.

Interstitial gamma irradiation by 198Au of the pituitary in diabetic retinopathy. Selective growth hormone blockade and ocular results.

Pituitary interstitial irradiation by stereotaxic implantation of a gamma pointemitter was performed in 110 patients with progressing diabetic retinopathy. Reduction of growth hormone secretion peaks was delayed, but was consistent and selective in all cases controlled by somatotropin stimulation test, while other pituitary secretions remianed unchanged in all but five cases. In 31 patients who had no associated photocoagulation, long-term postoperative assessment showed significant improvement of hemorrhages and intrarentinal new vessels with preservation of visual acuity. Preretinal vascular proliferation (except when treatable by photocoagulation), extensive retinitis proliferans, and macular deterioration are contraindications. This technique represents a new approach in the functional pituitary neurosurgical treatment of diabetic retinopathy and differs from all other procedures that result in a more or less complete hypophysectomy.

Dietary intake and other determinants of blood vitamins in an elderly population.

The relationships of diet, plasma lipids, age, gender, ponderal index, cigarette and alcohol consumption, drug use and infections to blood concentrations of retinol, beta-carotene, alpha-tocopherol, ascorbic acid and vitamins B1, B2, B6 status were studied among 291 men and women aged 60-82 years. Statistically significant correlations between dietary intake and blood indicator levels were found respectively for beta-carotene, alpha-tocopherol, ascorbic acid, vitamins B2 and B6, but not for retinol and thiamin, when the effects of other parameters were controlled. The main other determinants were cigarette consumption which had a negative effect on status for retinol, beta-carotene, alpha-tocopherol, ascorbic acid and vitamin B2; alcohol consumption for retinol, vitamin B6 (positive effect on status) and beta-carotene (decrease of plasma level); plasma lipids and use of hypolipaemic drugs for fat-soluble vitamins; ponderal index for beta-carotene and vitamin B6; gender and use of antibiotics for ascorbic acid. The apparent relation between gender and level of retinol, beta-carotene, alpha-tocopherol and vitamin B6 status was not any more significant after adjustment for alcohol or cigarette consumption. Tobacco and alcohol appear to be associated factors which should be controlled for in studies investigating relations between these vitamins and diseases influenced by smoking and drinking habits.

Effect of different kinds of dietary casein on blood cholesterol and triglycerides in pair fed rats.

After casein intake, serum cholesterol levels are dependent on many experimental conditions in rats. The effect of the method of casein preparation was assessed in Wistar rats pair-fed for 4 wk with three identical diets differing only by the type of casein used. Compared with dietary casein and Na caseinate, ingestion of lipid- and vitamin-free casein resulted in higher liver weights (4.35 +/- 0.23 vs. 3.89 +/- 0.30 and 3.90 +/- 0.25 g) and fasting serum cholesterol levels (0.55 +/- 0.13 vs. 0.49 +/- 0.09 and 0.44 +/- 0.09 g/L). Compared with the two other casein diets, ingestion of Na caseinate produced the lowest fasting serum triglyceride levels (0.62 +/- 0.13 vs 0.74 +/- 0.12 and 0.73 +/- 0.13 g/L). Peptic digestibility of caseins used might be a regulating factor of serum cholesterol levels in Wistar rats.

Ultradian, circadian and circannual rhythms of blood glucose and injected insulins documented in six self-controlled adult diabetics.

The aim of the study was to document during one to two years individual rhythmic patterns in blood glucose and injected insulin in self-controlled insulin dependent (C-peptide negative) diabetics with home blood glucose monitoring. Two females and four males with diurnal activity from 0700 to 2300 self-determined their blood glucose three to six times a day over a period of 12-27 months. Circadian and ultradian rhythms were analysed for each subject on a monthly basis to document annual rhythms. Blood glucose (BG) estimated circadian acrophases were located between 2200 and 0300 for all patients and months with few exceptions. A correlation was found between circadian mesors and amplitudes of BG in four subjects. Annual changes in BG were validated for each subject with large interindividual differences in peak times. The individual mean of injected insulin (II) varied from 40 to 80 iU with annual changes validated for each subject. A group pattern was observed with a peak time either in the autumn (four patients) or in the summer (two patients). A circadian rhythm of II was detected in almost all monthly means and for all patients. Locations of computed peak time phi of II exhibited a great stability for a given individual but large interindividual differences. Thus the rather constant phi location of BG for all subjects contrasted with interindividual differences in phi locations of II. These results suggest that rhythmic changes in BG and II should be recognized when forming a realistic strategy for timing and dosing time(s) of insulin.

Circadian and ultradian rhythms in blood glucose and plasma insulin of healthy adults.

The circadian and ultradian variations of blood glucose and plasma insulin have been characterized individually and as a group phenomenon in five healthy young adults studied while adhering as closely as possible to their usual routine of sleep, activity, meal content and timing. Three complementary methods were used to analyze the data: displaying raw data as a function of time; cosinor method according to Nelson and Halberg; and time series analyses as proposed by De Prins and Malbecq. The subjects were studied in the laboratory and their life routine were controlled, but very close to that of their habitual routine. They had mainly ultradian rhythms of blood glucose (mainly about 6 hr) and circadian rhythms of immunoreactive insulin (I.R.I.). Blood glucose ultradian rhythms seem to be mainly but not exclusively mealtime dependent, while I.R.I. circadian rhythms appear to be primarily endogenous in origin. Therefore, the role played by insulin in the control of blood glucose levels seems to be programmed on a circadian basis rather than by a time independent feedback phenomenon as postulated by the conventional homeostatic hypothesis. The advantage of this chronophysiologic approach is to consider circadian rhythms of both I.R.I. and insulin effectiveness as an adaptive phenomenon able to maintain blood sugar changes in the ultradian domain of rhythms.

Effects of breakfast-size on short-term memory, concentration, mood and blood glucose.

Effects of breakfast size on blood glucose, mood, short-term memory and concentration were assessed in 319 adolescents (age 13-20 years) in real-life setting. Mean energy increase of 63% over habitual breakfast had no effect on blood glucose or late morning mood. High energy intake from breakfast had a beneficial effect on immediate recall in short-term memory evaluated on the whole sample. However, concentration appeared to be impaired by a high caloric breakfast. There were no differences in the studied parameters according to energy supplement size. The present results are consistent with suggestions that meal size supplement has an effect on cognitive function.

Internal validation of a French version of the Dutch eating behaviour questionnaire.

This study is the first part of the validation of a French version of the Dutch Eating Behaviour Questionnaire (DEBQ), among a population of obese and normal-weight patients. The questionnaire was administered to 166 subjects. Construct validity was assessed by orthogonal factor analysis with a varimax procedure and reliability was measured by Cronbach's alpha coefficient. Results showed the presence of three major factors ("emotional", "restrained" and "external eating") with loadings similar to those of the original questionnaire. A high internal consistency was found in the different scales. This study clearly demonstrates the factorial validity and the reliability of a French version of the DEQB.

[Food allergy: effect of proteins-lipids and proteins-polysaccharides interactions]. / Allergénicité alimentaire: importance des interactions protéines-lipides et protéines-polysaccharides.

The most widely used ingredients in food formulation are proteins, lipids and polysaccharides. Proteins-lipids and proteins-polysaccharides interactions play a key role in the structure, stability, sensorial and nutritional properties of formulated foods. The objective of the present study is to highlight the importance of proteins-lipids and proteins-polysaccharides interactions, on the immuno-reactivity of allergenic proteins. Two models have been studied, on the one hand refined and not refined oils (soya and sunflower) and soya lecithin, on the other hand mixtures based on peanut proteins and polysaccharides (arabic gum, pectin, xylan). STUDY OF OILS: We have extracted proteins, using a PBS buffer, from refined and not refined oils from soya, sunflower and from soya lecithin, determined protein concentrations and identified allergenic proteins using SDS-PAGE electrophoresis and immuno-blotting. Phospholipids are determined by atomic absorption spectrometry. The protein determination and SDS-PAGE show the presence of a higher amount of proteins in not refined oils and lecithin as compared to refined oils. An important amount of proteins associated to phospholipids are eliminated by degumming on the form of lecithin. On the other hand, residual proteins from refined oils are accompanied by phospholipids. Immuno-blots reveal the presence of a 56 kDa allergen in oils issued from soya seeds and soya lecithin, and the presence of a 67 kDa allergen in oils issued from sunflower seeds. We conclude that the presence or elimination of proteins, especially allergens from oils is linked to amphiphilic association to phospholipids. STUDY OF PEANUT PROTEINS-POLYSACCHARIDES MIXTURES: We have digested in vitro proteins in a dialysis bag using a multi-enzymatic method and characterized proteins and peptides using SDS-PAGE electrophoresis and immuno-blotting. Our results confirm that peanut proteins alone are digested by proteases and that a number of large peptides still have epitopes recognized by anti-peanut proteins antibodies. Our results also show that the presence of polysaccharides changes the peptidic profile after digestion and that, depending on the polysaccharide type, smaller or larger peptides can be obtained in the dialysis bag. Smaller peptides are obtained using pectin whereas larger peptides are obtained using arabic gum and xylan. In the latter case, an increasing amount of peptides reacts to antibodies. Our first observations clearly show the need to better understand modifications of proteins allergenicity induced by the presence of other ingredients such as polysaccharides and lipids, in relation to technological treatments.