The role of carbon atoms of supported iron carbides in Fischer–Tropsch synthesis

High reactivity of iron carbides enhances the Fischer–Tropsch reaction rate on supported iron catalysts. Carbon atoms in iron carbide are involved in the initiation of chain growth in Fischer–Tropsch synthesis.

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.

Prévalence des déficiences et disparités sociales

BACKGROUND

Population ageing and longer duration of the working career could increase the prevalence of impairments and disabilities whereas there have been few data to help prevention and care. This study aimed at describing the prevalence of various types of impairments and assessing their social inequalities in the Lorraine population (north-eastern France).

METHODS

The sample included 6.214 subjects aged 15 or more from 8.000 households randomly selected in the Lorraine population. A mailed questionnaire including socio-demographical characteristics, job, and various types of impairments was used. The data were analysed with the chi2 independence test, the adjusted odds ratio (OR) and the Mantel-Haenszel test.

RESULTS

The prevalence of at least one impairment was 30% in both sexes. It varied from about 20% for subjects aged less than 40 years to about 60% for the subjects aged 70 years or more. It was higher in men than in women among the individuals aged more than 50 years (OR adjusted on age: 1.22, 95% CI: 1.04-1.44). The impairments were generally multiple for the subjects aged over 50. The prevalence of at least one impairment was higher for workmen (OR adjusted on age: 2.11, 95% CI: 1.68-2.66), farmers, craftsmen, traders and heads of firms (OR adjusted on age: 1.60, 95% CI: 1.17-2.18) and for employees (OR adjusted on age: 1.62, 95% CI: 1.29-2.03) in comparison with executives, intellectual professionals and teachers. For workmen a higher prevalence was observed for all types of impairments: intellectual and psychological functions, language, hearing, vision, visceral functions, and skeleton and posture. Farmers, craftsmen, traders, heads of firms and employees showed an excess for most types of impairments. Social inequalities were significant for various age groups during their period of occupational activity, but not after retirement. Unemployed people also had an excess of impairments.

CONCLUSION

The prevalence of impairments strongly increased with advancing age. Marked inequalities were observed between various socio-occupational categories. Men were more affected than the women over 50 years of age. Impairments represent a health index which is useful for prevention to reduce their causes and consequences.

[School-related injuries: incidence, causes, and consequences]

BACKGROUND

School accidents are frequent but little epidemiological information is available to guide prevention. In this study we examined the incidence, causes, and consequences of school accidents as a function of the pupil's characteristics.

METHODS

An epidemiological study was conducted in all 2 396 adolescents attending two secondary school groups. Sociodemographic characteristics of the pupils and data on school accidents during a one-year period were collected using a questionnaire filled out by the school nurse in the presence of the victims. The chi-square independence test, Fisher's exact test and the logistic regression method were used for the statistical analysis.

RESULTS

Sports and physical training (SPT) accidents accounted for 52.8% of the accidents, recreation accidents for 12.7% and other accidents for 33.6%. The annual incidence of one accident or more, for all types of accidents combined, was 12.9%, that for two or more accidents 2.3%. The rate of SPT and recreation accidents decreased strongly with age. SPT accidents were more frequent in girls, the other accidents more frequent in boys. Among the SPT accidents, 69.2% occurred under training conditions and 33.7% were caused by another person. Causes mentioned by the victims were: carelessness (26.0%), clumsiness (17.5%), misappreciation of risk (13.8%), tiredness (9.5%), nervous irritation (8.6%), rowdyism (6.0%), disrespect of the teacher's instructions (6.0%). The lesions were: contusions (50.7%), wounds (18.7%), tendinitis (11.7%), wrenches (9.2%), others (7.3%). They differed between age groups, sex, and category of sports. Localizations were mainly: fingers (27.4%), other localizations of the upper limb (20.1%), head (20.6%). A physician was consulted for 19.5% of the accidents and hospitalization followed 2.7%. Absence from school and exemption from SPT were frequent (11.4% and 16.3% respectively).

CONCLUSION

The results could be used to inform adolescents so they and their families could become more aware of the risk of school accidents. Prevention should mainly focus on the younger children. An effort must be made regarding risk assessment in order to help the pupils become more careful and responsible during their sports activities. The choice of these activities and the materials used should be made more suitable for adolescents.

Comment on "Finding finite-time invariant manifolds in two-dimensional velocity fields" [Chaos 10, 99 (2000)]

This note serves as a commentary of the paper of Haller [Chaos 10, 99 (2000)] on techniques for detecting invariant manifolds. Here we show that the criterion of Haller can be improved in two ways. First, by using the strain basis reference frame, a more efficient version of theorem 1 of Haller (2000) allows to better detect the manifolds. Second, we emphasize the need to nondimensionalize the estimate of hyperbolic persistence. These statements are illustrated by the example of the Kida ellipse. (c) 2001 American Institute of Physics.

Associations of family environment and individual factors with tobacco, alcohol, and illicit drug use in adolescents

Despite abundant literature the respective roles of psychosomatic status, personality, health perception, family environment, and sport activity in tobacco, alcohol and illicit drug use have not been well known. To assess their roles, an epidemiological cross-sectional study was conducted in 3294 middle and high school adolescents, 2396 (73%) of whom agreed to participate. The standardized questionnaire was filled out by the teenagers under the supervision of the teachers. Strong associations were found between tobacco, alcohol, and illicit drug use. The prevalence of alcohol use and illicit drug use were respectively 7 and 10 times higher in smokers than in non-smokers. On the whole, the potential risk factors for tobacco, alcohol, and illicit drug use were age, psychosomatic status and psychotropic drug consumption, boring family atmosphere, not living with both father and mother, and health perception. Mother being a housewife was a protective factor. No marked role was noted for the head of family's socio-occupational category. Personality would be indicators of self-control ability. Indeed, some self-reported personalities (serious, attentive, calm, organized) had protection roles whereas some others (easily irritable, aggressive, worried, clumsy, careless, solitary, etc.) were risk factors (risk-taking or deviant behaviors). Some sports activities were found to be negatively related, but some others related positively with drug use, possibly due to repetitive meetings between the adolescents at risk. Preventive measures may be targeted at these risk factors.

[A software for comparing ambulatory blood pressure measurements (ABPM)]

The software (MAPA-PC) for personal computers, designed by the author, provides precise and fast studies of ABPM, especially when comparing two anti-hypertensive treatments. It implies strict definitions of groups (e.g. dippers), indices (peak, trough, peak/trough ratio), and the type of smoothing of measured values: means (over 1, 2 or 3 hours) or smoothing by functions (polynomials or trigonometric series). The software calculates standard parameters (nighttime and daytime means, peak, trough...) as well as more original values (nighttime and period from points of inflexion in the curve, slope in these points, coefficients of variation on differences between 2 ABPM of a given subject...). It uses statistical tests (Mann and Whitney's U. Pearson's chi square, Snedecor's F) to compare results of treatment. It provides many types of curves (blood pressure lines, box-plots) which show kinetics and variability of blood pressure. The user can compare various types of smoothing (e.g. 2 vs 3 harmonics in Fourier series). The software was used on 237 records of 79 patients, in a randomized trial. It was written with Turbo Pascal and works on DOS personal computers. It is interesting for epidemiologic studies or clinical trials in which ABPM are used.

[Evaluation of the mortality related to nosocomial infections. An approach by a homogeneous group of patients, from bacteriology and data of hospitalization (1989-1993)]

We cross matched the informations from the medical records of the PMSI (French Program of Medicalisation of the Information System) with those from the bacteriology data base. The hospitalisation summaries provide the length of hospital stay, the mortality and the pathology defined by DRG (Diagnosis Related Group). Bacteriological data allow the diagnosis of nosocomial infections (NI) when using an appropriate methodology ("doubles" and early samples are not taken in account). Then it is possible to estimate the mortality when there are NI and No. 4499 stays NI were compared with 140,463 stays without NI. Mortality is 14.4% in NI group (17.5% in medecine and 8.6% in surgery) against 2.1% in the group without NI (2.5% in medecine and 0.8% in surgery). Among the 58 DRG's studied (more than 19 cases with NI), mortality and relative risk varie a lot. Results are estimations because they are many bias.

Fortuitous diagnosis of the association of hemoglobin J-Broussais with beta + thalassemia

The authors report a case, not described so far in literature, of an association of HbJ-Broussais [alpha (90 (PG2) lys-->asn beta 2] with beta + thalassemia in a young girl born of Italian father and Breton mother. This association is clinically silent. Biochemistry revealed, besides HbA, the presence of HbJ-Broussais in the proportion of 19.4% and HbA2 value of 3.9%. These percentages, slightly lower than expected, are explained. A familial study is presented.

Serum lipid, apolipoprotein and lipoparticle levels in the human fetus

Blood collected from 62 fetuses aged 20-38 weeks of gestation was studied. The values of ten lipid parameters were determined: cholesterol (TC), triglycerides (TGs), apolipoprotein A1 (apo A1), apolipoprotein B (apo B), apolipoprotein E (apo E), total apolipoprotein CIII (apo CIII), apolipoprotein CIII present in particles containing apo B (apo CIII LpB) or not (apo CIII Lp non-B), lipoparticles A1 (LpA1), and lipoprotein a (Lp(a)). The results show that, except for apo E, all the studied parameters were present in lower concentrations than in adults and newborns, and that Lp(a) is not detectable at that stage in life.

Increase in thiobarbituric acid-reactive substances and vascular complications in type 2 diabetes mellitus

Lipid peroxidation was assessed by measuring the concentrations of thiobarbituric acid-reactive substances in plasma from 204 Type 2 diabetic patients, relative to 107 controls. The concentrations obtained in diabetic patients (3.08 +/- 0.37 mumol/l) were significantly higher than in controls (2.80 +/- 0.34 mumol/l) (p < 0.0001). Values were also significantly increased in patients with macroangiopathy and/or microangiopathy (3.17 +/- 0.41 mumol/l), relative to patients void of vascular complications (2.92 +/- 0.34 mumol/l) (p < 0.001). Elevated concentrations were independent of the type of vascular complication and their possible associations. In patients without vascular affection, thiobarbituric acid-reactive substances were in significantly higher concentrations in hypertensive (3.07 +/- 0.36 mumol/l) than in normotensive (2.87 +/- 0.29 mumol/l) (p < 0.01) patients. There was a correlation between these values and those of total cholesterol (r = 0.46, p < 0.0001) and triglyceride (r = 0.45, p < 0.0001). Statistical analysis by multivariate logistical regression revealed that among the independent factors (TBARS, APO A1, hypertension, age), thiobarbituric acid-reactive substances constituted the parameter most strongly linked to the existence of vascular complications. This study has evidenced a lipid peroxidation disorder in non insulin- dependent diabetes mellitus, more marked in patients with vascular affection. Thiobarbituric acid-reactive substances appear to be an independent marker of vascular complications in Type 2 diabetes.

[Estimation with bacteriology of the evolution of nosocomial infections between 1989 and 1991 in an university hospital]

The bacteriological laboratory data base was studied with an original software (Bacterio) and an appropriate method ("doubles" and early samples are not taken in account) to estimate the nosocomial infections. The incidence rates for 100 hospitalizations at the University hospital of Nancy are 9.2, 8.2 et 8.2 for respectively 1989, 90 et 91. These values are corrected while taking into account a method's sensibility of 65%. The 1000 days of hospitalization's rates allow a better comparison between the medical departments. For the whole hospital, the results are respectively of 7.9, 7.2 and 7.5%. Even if the many bias described cannot always been checked, the method gives some evolutivity indicators which are very useful for the hygienists.

LDL sialic acid content in patients with coronary artery disease

Low density lipoproteins (LDL) are considered to be the most atherogenic of lipoproteins. These LDL can be modified and oxidative modifications are now well known. In addition, other atherogenic modifications of LDL exist, such as desialylation. In the present study sialic acid content was determined in LDL preparations obtained from patients with coronary artery disease (CAD+) and compared with that of healthy subjects and patients without coronary heart disease (CAD-). The sialic acid concentration was found to be statistically lower (P < 0.05) in the LDL of CAD+ patients (11.6 +/- 2.7 micrograms/mg of protein) than in the LDL of controls (16.5 +/- 5.6 micrograms/mg of protein) or in the LDL of CAD- patients (15.3 +/- 3.8 micrograms/mg of protein). In subgroups of CAD+ patients divided according to the severity of the disease, no statistically significant difference was observed in LDL sialic acid content. This work confirms the presence of desialylated LDL in the sera of patients with atheroma.

Plasma malondialdehyde in type 1 and type 2 diabetic patients

Malondialdehyde, a marker of lipid peroxidation, was measured as thiobarbituric acid reactive substances (TBARS) in 117 diabetic patients and 53 controls. Patients were divided into groups and subgroups according to the type of diabetes (type 1 and type 2) and the existence or not of vascular complication (macro- or micro-angiopathy). Results showed that TBARS concentrations were significantly higher in type 1 (P < 0.0001) and type 2 (P < 0.001) diabetic patients than in the control group. The plasma TBARS concentrations in type 1 and type 2 diabetic patients did not differ significantly. Among the patients with vascular disease, type 2 diabetic patients with macroangiopathy had significantly higher TBARS concentrations than patients with no vascular complication (P < 0.05). Whichever the type of diabetes, there was no correlation between TBARS concentrations and glycaemic control: glycosylated haemoglobin, fasting blood glucose. This study confirmed the existence of lipid peroxidation disorders in diabetic patients.

[Identification of a type 1 macrocreatine kinase]

A macrocreatine-kinase type 1 was identified by CK isoenzyme electrophoresis of a serum sample from a patient. Constituents of this enzyme complex were studied. The isoenzyme present in the macrocreatine-kinase was identified using immunoprecipitation with antibodies against the M subunit. Affinity chromatography then determined the type of the immunoglobulin bound to the CK isoenzyme. A protocol for studying macrocreatine-kinase type 1 compounds is proposed.

[Bacterio-expert: an integrated system for assisting in the validation of antibiotic sensitivity tests. Retrospective application in 4053 Staphylococcus]

Bacterio-expert is a simple expert system for assisting in the validation of antibiotic sensitivity testing. This system is incorporated in a data acquisition and editing program for bacteriologic test (Bacterio program written in Turbo-Pascal for personal computer users by the same authors). The principles of this system are explained and results with 4,053 antibiotic sensitivity tests on Staphylococcus aureus isolates are reported. Approximately 10% of tests required corrections.

Blood chemistry of human fetuses in the second and third trimesters

Six biochemical parameters and four enzyme activities were determined from the serum of 76 healthy and 56 pathological human fetuses between the 20th and 38th week of pregnancy. In the normal fetuses studied within that period, creatinine, immunoglobulin M, lactate dehydrogenase, and gamma-glutamyltransferase increased; haemoglobin F and glucose progressively decreased; and alkaline phosphatase was at a peak around the 26th week; cholesterol and triglycerides were always low. The same parameters were also measured in some of the pathological fetuses and compared with their normal counterparts.

Cutaneous interstitial fluid protein concentrations in the inflammatory syndrome: pharmacological consequences

Concentrations of alpha 1 acid glycoprotein, albumin, transferrin, haptoglobin, immunoglobulins G, A, M and apolipoprotein B were measured in serum and suction blister fluid from a group of individuals presenting a biologically proven inflammatory syndrome, and from a control group. Protein values in suction blister fluid did not change from the 2nd to the 3rd h after the beginning of blister formation. The ratio of the concentration of proteins in blister fluid and serum did not differ significantly between the groups. However, a 25% decrease in blister fluid albumin and a 100% increase in blister fluid alpha 1 acid glycoprotein, recorded in the inflammatory group, were worth noting, since they possibly influence the tissular distribution of some protein-binding drugs. Finally, an inverse relationship was established between the blister fluid/serum concentration ratio and the respective molar mass of each protein.

Comparative study of sucralfate versus cimetidine in the treatment of acute gastroduodenal ulcer. Randomized trial with 667 patients

Six-hundred sixty-seven patients with endoscopically proven peptic ulcer were included in a randomized, multicenter trial to assess the comparative efficacy of sucralfate and cimetidine. One hundred eighty-seven patients with gastric ulcer and 480 patients with duodenal ulcer completed the study. Ulcer healing was evaluated endoscopically at six weeks for duodenal ulcer and at eight weeks for gastric ulcer. Patients with unhealed ulcer at this time were assigned to the other therapy for a second period of six or eight weeks of treatment (crossover). In patients with duodenal gastric ulcer, pain relief and healing were not significantly different in the two groups. Eighty-eight percent of duodenal ulcers and 73 percent of gastric ulcers healed with six weeks of sucralfate treatment. Reported side effects and symptoms, pooled together for duodenal and gastric ulcer, were more significant in the sucralfate group (7.5 percent) than in the cimetidine group (3.7 percent). Constipation was the most frequent symptom recorded. In conclusion, sucralfate and cimetidine are both excellent healing agents for short-term treatment of duodenal and gastric ulcer. Both give rapid relief of symptoms without severe side effects.

Amodiaquine-induced agranulocytosis: report of a case with in vitro studies of granulocyte-macrophage progenitor cells

We report a case of amodiaquine-induced agranulocytosis in a 60-year-old woman. Four months after the agranulocytosis episode we investigated the effect of the drug using in vitro agar culture techniques. Amodiaquine at increasing concentrations (0.005, 0.05 and 0.5 microgram/ml) displayed an inhibitory effect, probably dose-dependent, on the growth of the patient's bone marrow GM-CFU colonies in the absence of autologous serum. In contrast, no effect was found on the colony and cluster growth of bone marrow samples from 13 healthy controls. Though it has been shown in several cases that amodiaquine-induced agranulocytosis occurs via immune-mediated mechanisms, our data are in support of a direct toxic effect of the drug on abnormally sensitive myeloid progenitor cells.

Toxicity of HPA-23 (ammonium-21-tungsto-9-antimoniate) for normal human myeloid progenitor cells (GM-CFU) in vitro

HPA-23 is a competitive inhibitor of the RNA-dependent DNA polymerase (reverse transcriptase) of the human immunodeficiency virus (HIV). It may therefore potentially benefit patients with HIV infection. This study aimed at defining the haematopoietic toxicity of this drug and particularly its effects on the normal human granulocyte-macrophage progenitor cells (GM-CFU). Our in vitro studies, in semi-solid agar, have shown an inhibitory effect of increasing concentrations of HPA-23 on colony and cluster formation. This effect is probably dose-dependent. An almost complete inhibition of colony formation was observed at doses of more than 20 micrograms/ml. Regarding cluster formation, a similar although much more progressive inhibitory effect was found. Our experimental data should be extrapolated with caution to clinical situations. However, they must be kept in mind for optimal design of HPA-23 therapy in HIV infected patients.

Level of plasma fibronectin in patients with breast cancer

Plasma fibronectin was determined by laser nephelometric immunoassay in two populations: healthy individuals and patients with metastatic or non-metastatic breast cancer. The results showed that the fibronectin concentration was higher in the patient group than in the healthy controls of similar age, with a significant difference (p less than 0.05). The patients who had metastatic breast cancer tended to show higher levels than those with no detectable metastasis, but such a difference was not statistically significant. Since fibronectin is sensitive to clinical events unrelated to the malignancy status, it does not seem suitable as a tumor marker.

[Applications of a simple system of aid to medical decision-making with various patients in internal medicine: SELF]

Many medical decision helping systems are very complex and require expensive computers, which restricts their diffusion and limits their use to specialized people. The idea was to find a simplified system that any practitioner--even unaccustomed to microcomputing--would be able to use. Moreover, this system had to work on widely available and inexpensive microcomputers. SELF (system in fuzzy set) is this kind of system. It has been devised as a complete interactive system of medical decision help. It is entirely parameterized, allows any kind of application and works according to such rules as "if there is premise, then there is conclusion", tempered by a coefficient. The bases of knowledge are represented on a correspondence chart where columns materialize the premises (clinical signs, laboratory results, etc.) and horizontal lines all the diagnoses and therapeutic conclusions. The system includes proceedings that create, modify and update basic knowledge. It uses the fuzzy set rules to draw conclusions. SELF was first applied to the prescription of contraceptive methods, but it has now been tested in other specialties, such as gynaecology, pneumology, haematology and so forth. In every case, the reliability of the results obtained depends on the bases chosen by the creator himself. Owing to the general character of the system, one may regard it as being open to any user who would like to create his own applications.