Biochar as a sustainable alternative to carbon black in agricultural mulch films.

Examples of biochar as an alternative to traditional plastic fillers, like carbon black, are numerous and growing. However, in the agricultural mulch film application, both the polymer and its fillers are pushed to their mechanical limit to obtain an effective product, using the least amount of plastic. Through a combined techno-economic analysis (TEA) and life cycle assessment (LCA), this study characterizes the use of carbon-negative biochar as an opacity filler in mulch film applications. Due to its larger particle size, the biochar demands additional thickness to achieve equivalent opacity as carbon black in films. A thicker film translates to additional polymer demand, and a significant increase in price and environmental impact. A comparable formulation for an equal price ($623 per mulched ha) as a 2.6 wt % carbon black with 25 µm thickness was derived, needing 15 wt % biochar and a thickness of 30 µm. The biochar formulation resulted in a slightly higher global warming potential (3% increase), but much larger impact in the land use category (+339%), and the sample was deemed not fit for use in the intended mulch application. These results indicate that in applications where the polymeric matrix and its fillers are pushed to their mechanical limit, the displacement of traditional fillers by biochar is challenging. However, biochar derived from waste biomass (thus reducing land use impact) remains a valid, environmentally beneficial solution to displace traditional fillers for non-extreme plastic uses (commodity plastics) and thicker composites.

[Osteoarticular disease in adults in France. A survey of 2000 persons]. / Pathologie ostéo-articulaire de l'adulte en France. Enquête auprès d'un énchantillon de 2000 personnes.

PURPOSE OF THE STUDY: Seeking for a global epidemiology data on bone and joint disease in adults in France, we analyzed the problems related to bone and joint disease in a sample population to determine healthcare needs. We also examined patient referral and demand for surgical care for bone and joint disease and the degree of patient satisfaction. MATERIAL AND METHODS: A telephone interview was conducted in a randomly sampled population of adults living in France to determine their demographic characteristics and bone and joint conditions and surgical care reported by the interviewees. Before standardizing, the sample population in the 60-year and older group was increased in order to obtain more precise information concerning degenerative joint disease. The sample included 1000 persons aged under 60 years and another 1000 persons aged over 60 years. The sample populations were matched to the French population for sex and age distribution. One hundred personal face-to-face interviews were also conducted with 100 persons residing in a nursing home. The two surveys were conducted in June and July 1999. RESULTS: Extrapolation of the data obtained to the French population yielded a total of 12 million adults affected by a bone and joint condition during the year preceding the survey. Considering both study samples, the most frequent localizations concerned the spine and the knees. The distribution of the other localizations was age and sex dependent. The percentage of trauma-induced conditions was 31%, predominantly in men under the age of 60 years and in institutionalized individuals. Extrapolation yielded a total of 5.4 million persons who had (or expected to have) a surgical intervention due to a bone and joint condition. The percentage of surgical treatment was highest for fractures (41%) and extravertebral osteoarthritis (18%). Extrapolation to the French population yielded 0.55 million persons aged over 60 years with a hip prosthesis and 0.27 million with a knee prosthesis. Seventy-six percent of the individuals who had undergone surgery for a conditions unrelated to trauma felt their quality of life had been improved. For those who had surgery for a trauma-induced condition, 85% considered they had minimal or no sequelae. Information provided by the surgeon concerning surgical care was thought to be insufficient by 23% of the operated individuals and 43% of those who had a joint prosthesis stated they had not been informed that their implant might be changed. Management of postoperative pain was thought to be insufficient by 36% of the operated individuals. DISCUSSION: Due to the wide field of investigation and the methodology used to collect these data, our findings cannot be easily compared with other epidemiological data. They must be considered with caution due to the sampling bias of a telephone interview and also to the bias introduced by the simplified nosology scheme used for the questionnaire and the fact that no medical validation was performed. These data do however show that a large number of adults are concerned, notwithstanding conditions occurring before the age of 18 years with the frequency of accidents during childhood and adolescence. The data collected confirm the priorities set within the framework of the Bone and Joint Decade 2000-2010.

[Two years follow-up of a heroin users cohort treated with high dosage buprenorphine. Results of the SPESUB study (pharmacoepidemiologic follow-up of general practice Subutex)]. / Suivi à 2 ans d'une cohorte de patients sous buprénorphine haut dosage. Résultats de l'étude SPESUB (suivi pharmaco-épidémiologique du Subutex en médecine de ville).

BACKGROUND: Since February 1996, French GPs are allowed to prescribe high dosage buprenorphine for maintenance treatment of major opioid drug addiction. A prospective cohort of major opioid addicts was initiated in order to assess patient outcomes: follow-up, retention rate in treatment, drug use, intravenous injection and social situation evolution. METHODS: Each GP, known to be involved in drug user management, had to include the first 10 opioid drug addict patients to whom he prescribed high dosage buprenorphine, with a maximum inclusion period of 3 months. Patients were followed up for two years and a regular standardized information was collected (usual data on drug users and prescription modalities). RESULTS: Between May and July 1996, 919 patients (664 men and 255 women, mean age: 30 years) were included by 101 GPs. They had a long and serious history of drug addiction, important parallel consumption of cocaine, codeine and other illicit drugs and psychiatric problems (28% of definite problems and 45% of probable) and frequent hepatic conditions (hepatitis B: 23%, hepatitis C: 21%). Two years later, 55% of patients were still followed-up by the same GP and an additional 12% were followed by another GP or in a health care service (hospitalized or receiving methadone in a specialized centre). 13% were not followed, but GPs were able to describe their situation. 8% had been included by GPs who had dropped the study. Finally, 12% of patients were lost to follow-up. Among the 508 patients still followed-up by the same GP after 2 years, the substitution treatment rate was 84%. The dosage bracket had widened (inclusion: mean dosage=7.8 mg +/-4.5, minimum=0.8, maximum=28, median=8; after 2 years: mean=7.6 mg +/-5.4, minimum=0.4, maximum=28, median=8) and the duration of the prescription and dispensing had increased. Declaration of heroin intake in the previous month had fell from 40% to 11% and declaration of drug intake from 53% to 20%. Social situation had improved on average (housing conditions and work). There were 12 seroconversions for hepatitis B, 21 for hepatitis C and 4 for HIV. 14% of patients had declared intravenous injection of high dosage buprenorphine in the previous month. CONCLUSION: After two years of follow-up, 55% of patients were still followed-up by the same GP and an additional 12% was followed by another GP or in a health care service. Among patients still followed up by the same GP, a reduction of drug related harm (seroconversions for hepatitis B, hepatitis C and HIV) was observed.

Pregnancy-induced changes in lower extremity superficial veins: an ultrasound scan study.

OBJECTIVE: The purpose of this study was to follow changes in superficial veins of the lower extremities during pregnancy and the postpartum period in women with varicose veins. METHODS: This was a prospective study with the use of duplex scanning during the first and third trimesters of pregnancy and postpartum period. Competent veins were defined as veins with an absence of reflux, and incompetent veins were defined as veins with reflux. The diameter of the competent or incompetent greater saphenous vein (GSV) and lesser saphenous vein (LSV) was measured. The diameter of the largest varicose dilatations was measured in all three networks: GSV and its tributaries, LSV and its tributaries, and nonsaphenous varicose veins. RESULTS: Sixty-six women were studied prospectively (mean age, 32.2 +/- 4 years; 85 affected extremities). The diameter of competent and incompetent GSVs and competent LSVs increased between the first and third trimester (P <.001) and decreased between the third trimester and the postpartum period (P <.001). The diameter of the largest varicose dilatations of the GSV and its tributaries and nonsaphenous networks increased between the first and third trimester (P <.001) and decreased between the third trimester and the postpartum period (P <.001). No statistically significant variation of the diameter was demonstrated for any of these veins between the first trimester and the postpartum period. CONCLUSION: The diameters of competent and incompetent superficial veins increased during pregnancy and decreased during the postpartum period to return to their baseline values.

[Motivations and risk factors for tobacco use in new members of non-smoking youth clubs]. / Motivations et facteurs de risque tabagique chez les nouveaux adhérents des clubs de jeunes non fumeurs.

Since 1990, the National League Against Cancer and its departmental committees have put in place non-smoking clubs for youth (Club Pataclope) in order to carry out smoking prevention actions for youth between the ages of 7 and 14 years. The organisation of these actions is the responsibility of each of the different clubs. This study aims to describe the profile of new members, their motivations for joining the Pataclope Clubs, and their risks concerning tobacco consumption. A survey by close-ended self-questionnaire was carried out among new clubs members.

[4-month follow-up of 198 heroin addicts by general practitioners]. / Suivi à 4 mois de 198 héroïnomanes par des médecins généralistes.

This study aimed to describe the short term follow-up of a cohort of 198 i.v. heroin users by 44 highly motivated General Practitioners (GPs). The study showed that for these GPs, the work-load linked with the care of these patients was heavy. Nearly half of them saw at least one drug-addict every day. These GPs work within a network and stated they benefit from a regular training on drug addiction topics. The profile of i.v. heroin users, followed by these GPs, is different from the ones usually described in other health care structures (higher percentage of women and better social insertion). The two main motives to consult a GP are the demand of drugs concerning their addiction and medical concern (due to infectious diseases especially). The answer of GPs, concerning the demand of drugs, divide physicians into two groups: those who never prescribe morphine like drugs as substitution and those who do so. In addition, both of them often prescribe psychotropic drugs to some of their patients. Nevertheless, these prescriptions are just one of the elements of a follow-up contract between a GP and his patients. Morphine like prescription is more frequently described among long term drug-addicts already well-known by GPs. This selection prohibits a straight comparison of the results of two groups of patients (with and without morphine like substitution). But the main fact is that patients under morphine like substitution are followed better (in terms of continuity) after 4 months of observation.

[Effects of an educational campaign on cardiovascular risk factors in a French town (Epernon, study town). Methods and preliminary results: prevalence and level of risk factors]. / Influence d'une campagne d'information sur les facteurs de risque cardiovasculaire dans une ville française (Epernon, Ville d'Etude). Méthodologie et résultats préliminaires: prévalence et niveau des facteurs de risque.

The authors report the methods and preliminary findings of a study scheduled to last 5 years, which aims to evaluate cardiovascular risk factor changes in response to an education program. The population sample consisted of 961 subjects, from Epernon itself (the study town) and from two control towns. The assessment criteria were reported at the beginning of the study and then again after 2 and 5 years. They consisted of an analysis of medical events and of biomedical and dietary data and a detailed analysis of behavior with regard to health and socio-economic variables. Preliminary data show that the samples were similar in Epernon and the control towns and also comparable to some French epidemiological data. There is a striking difference between the percentage of subjects aware of their blood pressure (65.5%) and blood cholesterol (13.4%) levels.

[Management of drug addicts (heroin addicts) by general practitioners]. / La prise en charge des toxicomanes (héroïnomanes) par les médicins généralistes.

A telephone survey has been undertaken in a random sample of 150 General Practitioners (GPs) in four regions of France. 25% refused to answer. The study showed that drug addiction (use of heroin) is a serious issue for many of these physicians: 15% follow more than 20 drug addicts per year and only 12% see none; extrapolating the mean number of drug addicts followed yearly (9.4 per GP) to all GPs in the four regions (26,000, that is to say half of all french GPs) give an "active file" of 250,000 drugs addicts per year. Only 15% if the GPs feel they are educated for the management of drug addicts, although 70% say they prescribe medication such as hypnotics and anxiolytics (97%), the most cited being Tranxene 50 (Chlorazepate 50 mg), antalgics (84%), morphinic or morphine-like drugs (49%), mainly Temgesic, and at last antidepressants and neuroleptics (39%). GPs suffer from being isolated in their practices, as contacts with collegues or institutions specialized in drug addiction are few. If one third of the GPs wish an active participation in the management of drug addicts, and one third wish at least to "do something", they are all much ambiguous in their attitudes toward drug addiction. Their behaviors vary from medical pride to anxiety and even fear. They all mention a lot of practical problems with respect to reputation, practice, lack of time... Unanimous wishes concern opportuneness of setting up continuous medical education on this topic, of working out guidelines for prescription, of improving relationships with other institutions.

[Current practice and attitude of anesthesiologists for prescribing preoperative investigative tests]. / Pratiques et attitudes actuelles des médecins anesthésistes en matière de prescription d'examens paracliniques préopératoires.

A telephone enquiry was undertaken to assess current practice among French anaesthetists, and to obtain their opinion, concerning preoperative laboratory screening tests. It included 204 anaesthetists, randomly selected from the membership directory of the French Society of Anaesthetics and Intensive Care. The sample was concordant with the distribution (sex and age) given by the specialists' list of the National Medical Council. It comprised 64.2% male anaesthetists, and the overall mean age was 44.2 years. On average, each anaesthetist carried out 26 elective and 4 emergency anaesthetist a week. An organized preanaesthetic consultation was available in only 73% of public hospitals. However, even when existing, it does not automatically concern all surgical stations of the hospital and only 59% of patients benefit from that consultation. In 55% of patients the screening tests had still been made before the preanaesthetic consultation for scheduled surgery. About 15% of patients were seen for the first time by an anaesthetist on the very day of surgery. A routine prescription of preoperative tests was not systematic. Non prescription ranged from 7 to 34% of patients, depending on the tests. The responders recognized that for the same tests the rate could be comprised between 21 and 66% of patients. Moreover, 38% of anaesthetists admitted that sometimes they did not see results of the prescribed tests before carrying out the anaesthetic. Overprescription of preoperative tests has been recognized. However, legal, organisational, relational or economical reasons are given which may explain difficulties met with to rationalize prescription of these tests.

[Computer simulation of the 10-year outcome of a cohort of heroin addicts in Ile-de-France]. / Simulation informatique du devenir à 10 ans d'une cohorte d'héroïnomanes en Ile-de-France.

The aim of this study is to develop a computer simulation model to describe imaginary cohorts of heroin users in the Ile de France (greater Paris) region. Because of the lack of well-designed cohort studies in France, this model is based on epidemiological data found in various different studies. The results of the simulation reveal horrifying outcomes in ten years' time: in the more optimistic scenario (an annual non-Aids mortality rate of 1%, an annual rate of permanent addiction curtailment of 10% and a syringe exchange rate of 10%), only 50% of heroin users curtail their consumption permanently without being HIV carriers after 10 years, 16% are HIV carriers and 10% have died. In conclusion, medical care should play an important part in the management of drug users, and secondary prevention aimed at reducing the health problems involved in heroin use should be intensified.

Selective contraindications based on multivariate analysis for operative cholangiography in biliary lithiasis.

This study was done to select patients with a low risk of common bile duct (CBD) stones in whom operative cholangiography could be avoided. Operative cholangiography was performed upon 511 patients. Two different groups of patients were identified--patients with CBD stones visualized by CBD exploration (n = 90) and patients with no CBD stones at the time of operative cholangiography (n = 421). Multivariate analysis (stepwise logistic regression) showed that five variables were correlated with the presence of CBD stones--size of CBD equal to or greater than 12 millimeters, gallstones equal to or less than 10 millimeters, advanced age, chronic or acute cholecystitis and past history of biliary colic. Using a scoring system, a group of patients with a low risk (less than 2 percent) of CBD stones could be easily determined. In this group of patients, operative cholangiography may be avoided.

Prospective assessment of a protocol for selective ordering of preoperative chest x-rays.

Routine preoperative chest x-rays are still widely employed worldwide, although results of many studies do not support their broad utilization. A protocol for selective ordering of preoperative chest x-rays, according to the patient's clinical status, medical history and scheduled surgery, was developed and implemented in a teaching hospital in Paris. The utilization of the protocol during a one-year period was evaluated. Eleven hundred and one chest x-rays were ordered in 3866 patients (28 per cent). Five hundred and sixty-eight x-rays (52 per cent) were abnormal. One hundred and sixty-six (15 per cent) were considered useful by the anaesthetists, who took into account the entire hospital course, although only 51 (5 per cent) had an impact on the surgical plan or anaesthetic management. Among the 2765 patients who did not have a preoperative chest x-ray, two patients could have benefited from the chest x-ray, in the view of anaesthetists. Chart review for these two patients and for patients who had perioperative complications in the absence of a preoperative chest x-ray revealed that no complications could be linked to the lack of preoperative chest x-ray ordering. This study shows that the abandonment of routine ordering of preoperative chest x-rays does not produce adverse effects on patient care.

[Effects of simvastatin on plasma lipids, lipoproteins and apoproteins (A1 and B). 24 cases of major primary hypercholesterolemia]. / Effets de la simvastatine sur les lipides, lipoprotéines et apoprotéines (A1 et B) plasmatiques. 24 cas d'hypercholestérolémie primaire majeure.

We studied the effects of simvastatin (MK 733), a new competitive inhibitor of HMG CoA reductase, alone and in combination with a bile acid sequestrant, cholestyramine, on serum levels of lipoproteins and apoproteins A1 and B, in 24 patients with familial hypercholesterolemia. After simvastatin treatment (40 mg/day) alone for 12 weeks, serum total and low density lipoprotein cholesterol decreased by 31 and 36 percent respectively. With the addition of cholestyramine, there was a 41 per cent total decrease in serum cholesterol from the control value and a 50 percent decrease in low density lipoprotein cholesterol. After cholestyramine treatment alone for 12 weeks, serum total and low density lipoprotein cholesterol decreased by 20 percent and 29 percent respectively. With the addition of simvastatin (20 mg per day), there was a 32 percent total decrease in serum cholesterol from the control value and a 43 percent decrease in low density lipoprotein cholesterol. High density lipoprotein cholesterol remained unchanged. No major adverse effect was observed. If long term safety can be confirmed, the simvastatin-cholestyramine regimen may prove useful in heterozygous familial hypercholesterolemia.

Usefulness of selectively ordered preoperative tests.

The authors prospectively evaluated the usefulness of 12 preoperative tests (including blood type and screen) ordered selectively according to clinical status and importance of scheduled surgery. Two methods of assessing usefulness of tests were used, taking into account not simply their abnormality yield, but also their impact on patient care during the entire hospitalization: first, usefulness was assessed by anesthetists involved in care; second, usefulness was assessed by an automated analysis of specific clinical situations in which tests were a priori considered useful. In 3,866 patients 15,920 tests were performed; 30% of performed tests were abnormal. As a consequence of test results, surgery was delayed or cancelled in 19 patients and modified in 1, and a treatment was instituted or anesthetic management influenced in 347 (9%). Blood component therapy was instituted in 652 patients (17%). Anesthetists and automated analysis found at least one preoperative test useful in 931 patients (24%) and 890 patients (23%), respectively, whereas on a per-test basis 17% and 9% of tests were found useful. The discrepancy in usefulness assessment was mainly due to differences in evaluation of the usefulness of normal results. This study shows that the usefulness of selectively ordered preoperative tests may be high, but better criteria for their indications are needed, because tests other than those recommended by protocol were found useful.

[Evaluation of a protocol for selective ordering of preoperative tests in healthy subjects]. / Evaluation d'un protocole de prescription sélective des examens paracliniques préopératoires chez des sujets sains.

A protocol for selective ordering of 12 preoperative tests was prospectively evaluated during one year in a teaching hospital. 1600 consecutive healthy patients had an average of 2.4 tests each, but 270 of them had none. Usefulness of tests was assessed by taking into account not simply their abnormality yield, but also their impact on patient care during the whole hospital stay in the anaesthetist view. The possible value of tests omitted was assessed by anaesthetists at the end of hospital stay. As a consequence of test results, surgery was delayed in one patient, and a treatment was started or the anaesthetic management adapted in 16.7% of tests performed (279/3905) were found to be useful and 0.1% of tests not carried out (21/15295) would have been potentially useful. No complication inducing sequelae or death could be linked to tests not carried out. This study showed that routine preoperative investigations in healthy patients could be avoided without any adverse effects on patient care.

Essential thrombocythemias. Clinical evolutionary and biological data.

This retrospective study reviewed 94 patients, aged 6 to 90 years, with thrombocythemia. The women/men ratio was 1.76. At onset or, less commonly, during the course of the disease, 45% of the patients presented hemorrhagic manifestations, 29% thrombotic complications, and only 14% the association of hemorrhage and thrombosis. The average platelet count was 1200 X 10(9)/1, with no difference according to sex or age. Platelet hypoaggregation was seen in practically all the cases (94%), although myelofibrosis was less frequent (54%). The frequency of hemorrhages increased when the platelet count was above 1000 X 10(9)/1 (P less than 0.01), but the occurrence of thrombosis was correlated neither with platelet count nor with thrombopathy. Survival time was lengthy: 80% of survival (standard error 6%) was observed at 100 months. Transformation to acute leukemia was observed in five patients. Because the disease course is most often prolonged, therapeutic measures must be conservative: anti-aggregating drugs in small doses, and chemotherapy beginning with nonalkylating agents.

Evaluation of a protocol for selective ordering of preoperative tests.

A protocol for selective ordering of 12 preoperative tests, according to clinical status and type of surgery, was prospectively tested for one year in a teaching hospital. 3866 consecutive surgical patients had an average of about 4 tests each. The possible value of tests that were omitted was assessed in the light of events during and after operation. According to predetermined criteria, 0.4% of non-ordered tests would have been potentially useful; but in the opinion of the anaesthetists, only 0.2% would actually have been useful. The protocol therefore had little adverse effect on patient care and was acceptable to clinicians.

Prognostic factors from a randomized clinical trial in resected lung cancer.

Prognostic information has three main uses: prediction of the course of evolution of disease, decisions about treatment and limitation of complementary tests. Using data from a randomized controlled clinical trial of immunotherapy in resected lung cancer, we identified factors of prognostic importance. In particular we demonstrated that a time-consuming and expensive cell-mediated immunity test is not of prognostic value. Our cooperative group decided to cancel this test in the routine examination of patients with resected lung cancer. Disease stage was confirmed as the main prognostic factor.

[An approach to the evaluation of medical journals: application to original articles of La Presse Médicale and the New England Journal of Medicine published in 1982]. / Une approche de l'évaluation des publications médicales: application aux articles originaux de La Presse Médicale et du New England Journal of Medicine parus en 1982.

Medical journals play an important role in the diffusion of scientific medical information. We tried to evaluate the French medical journal, La Presse Médicale, and to compare it with the New England Journal of Medicine. We reviewed all the original articles published in 1982 (207 articles In La Presse Medicale and 152 articles in the New England Journal of Medicine): specialties, methodologies used in the studies, environment (number of authors, geographical origin, institutional origin, number and language of references, number of subjects included in the studies). The articles in both journals concerned virtually the same specialties, more than 50% of the articles dealing with the following: cancerology, cardiology, infectious diseases, endocrinology, gastroenterology. Many specialties including highly prevalent diseases were underrepresented in both journals. When treating the same kind of problems, different methodologies were used: faced with a therapeutical problem, authors in La Presse Medicale used mostly non controlled evaluations (46%, 30 articles), and few randomized controlled trials (12%, 8 articles). On the other hand, authors in the New England Journal of Medicine used mostly randomised controlled trials (56%, 36 articles), and less non controlled evaluations (26%, 16 articles). Most references were in English, even in La Presse Medicale, in which 76% of all references were not in French, and 14% of all articles had no French references. In conclusion, this study shows differences between the two journals: in particular, the methodologies used by the authors in La Presse Medicale were less pertinent than those used by the authors in the New England Journal of Medicine. This finding is important with regard to the formation of and information given to the French speaking physicians, and a strong reaction from the editors and physicians concerned is desirable.