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Biomedical subjects

C Chastang

Publications and source records attributed to C Chastang.

At least 181 records · Page 10Linked to original sources
PubMed1987

[Evaluation of a protocol for selective ordering of preoperative tests in healthy subjects].

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.

Adult↗
PubMed1987

Consequences of renal morphologic damage induced by inhibition of converting enzyme in rat renovascular hypertension.

The consequences of morphologic changes in the kidney distal to a stenosis induced by chronic administration of a converting enzyme inhibitor were determined after induction of experimental renovascular hypertension in rats. The relationship between changes in morphology in the clipped kidney and diuresis, creatinine, and mortality was studied by converting a two-kidney, one-clip model into a one-kidney, one-clip model after 1 month of converting enzyme inhibition. The right renal artery was constricted with a clip of 0.2 mm diameter to increase blood pressure, the left kidney was left untouched. After 1 month, systolic blood pressure had increased to 173 +/- 27 mm Hg in the clipped animals (n = 47) compared with 139 +/- 8 mm Hg in sham-operated animals (n = 15; group 1). An inhibitor of angiotensin-converting enzyme, MK421 (2 mg/kg, po), or an equivalent volume of vehicle was then administered daily for 1 month. After treatment with the converting enzyme inhibitor, blood pressure (148 +/- 28 mm Hg) was virtually identical with that of a sham-operated, vehicle-treated control group (145 +/- 16 mm Hg, n = 15), and was significantly lower than that of untreated hypertensive rats (186 +/- 30 mm Hg, n = 17) (group 2). The weight of the left kidney was increased in the untreated hypertensive animals as compared with sham-operated controls (1260 +/- 168 mg for group 2 versus 1075 +/- 100 mg for group 1). After treatment with MK421, the weight of the contralateral kidney (1472 +/- 190 mg) was further increased. After 1 month of treatment with MK421 or vehicle, the unclipped left kidney was removed from all animals. The treated animals were then randomly divided into two groups: one in which treatment with MK421 was stopped (treated/untreated, n = 24; group 3) and a second in which the treatment was continued (treated/treated, n = 23; group 4). The ability of the rats to excrete a water load of 15 ml was then examined 12 hours after removal of the unclipped left kidney. In the two groups of treated rats, the urinary excretion of the water load was decreased and frequency of oliguria was increased as compared with controls and hypertensive untreated rats. Survival rates were affected by the treatment: 3 deaths occurred in the hypertensive untreated group 2, 10 in the treated/untreated group 3, and 12 in the treated/treated group 4. The majority of these deaths could be attributed to renal insufficiency.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1987

[Initial clinical and paraclinical findings in 304 small cell broncho-pulmonary cancers of the 01 PC 83 trial].

Three hundred and four cases of small cell lung cancer diagnosed histologically were included in a randomised multi-centre trial (23 centres) from 1st January 1983 to the 30 September 1985, with no clinical criteria for exclusion. The clinical and laboratory data were taken from the initial assessment of the patients in the trial, and were compared with those in the literature. The sex ratio was 10:1, only 27 were women (9%) and all were less than 70. The mean aged was 60 +/- 10 (extremes 33 to 84 years) and 80% of the population was from 40 to 70 years. Tobacco consumption was virtually constant, only 7 were non-smokers and 7% of patients smoked less than 20 packs/year; indeed consumption was very heavy with a mean of 44 +/- 23 packs/years. 14% of cases were discovered on systematic radiological examination, but 39% of these asymptomatic patients already had disseminated disease. For the 304 patients overall, despite a very variable degree of dissemination from one patient and one centre to another, 163 (54%) had disseminated disease at the outset and 141 (46%) were apparently localised. The initial metastases were often multiple: extra-thoracic nodes (21%), hepatic (23%), osseous (20%), bone marrow (23%), cerebral (9%), and others (9%); these frequencies are underestimated in view of the fact that the investigations were not over-extensive. The serum carcino embryonic antigen levels were abnormal in 32% of cases. Fibroscopy remains the main diagnostic method to provide the histological proof for 90% of patients, but 4% had thoracotomies (of whom 3% were diagnostic thoracotomies).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

[Prognostic factors in operated non-small cell cancer of the lung. Study from a randomized therapeutic trial].

This article presents the results of a prognostic study of primary resected lung cancer (non-small cell). The data result from a randomised clinical trial of immunotherapy with a non-specific adjuvant; the follow-up was between four to seven years. Thirty-five clinical, biological and anatomo-pathological parameters were gathered at the time of inclusion in the trial. The response criteria used were survival without recurrence and total survival. A multivariate analysis using the Cox's model was carried out for each criterion. At the reference date of the 1st April 1985, 125 relapses and 132 deaths were counted amongst 219 patients; there was only one patient lost to follow-up and only 39 missing data were observed. The negative therapeutic results of the immunotherapy used were confirmed by this new intermediate analysis. The rate of survival without recurrence at 5 years was 43% and the overall survival at five years was 42%. The use of Cox's model to show the prognostic information at the 5% level for survival without recurrence could be summarised by five factors: main staging (the prognostic factor), leucocytosis, the cutaneous reaction to proteus, Karnofsky index and presence of physical signs. For stages I and II the outcome was identical and no factor was predictive at the 5% level. For stage III the cutaneous reaction to proteus and leucocytosis were prognostic. For overall survival, the prognostic information at the 5% level could be summarised by five factors: staging (main prognostic factor), leucocytosis, Karnofsky index, presence of physical signs and lymphocytosis. For stages I and II whose outcome was identical only Karnofsky index and lymphocytosis were predictive at the 5% level.(ABSTRACT TRUNCATED AT 250 WORDS)

Carcinoma, Non-Small-Cell Lung↗
PubMed1987

New trends in CLL treatment.

We review here results obtained from the various treatment modalities that have been used in CLL patients: chemotherapy; radiotherapy; splenectomy; leukapheresis; monoclonal antibodies and other immunomodulating agents. We conclude that it is still unclear whether patients in stage A (good prognosis) should be treated; intermediate forms of the disease (stage B) should, in most cases, be treated, but a better treatment than chlorambucil has not emerged; results from the Cooperative Group on CLL of Société Française d'Hématologie indicate that significant progress in the therapy of the advanced stage (stage C) has been achieved with the introduction of the CHOP regimen, using low doses of adriamycin; radiotherapy, splenectomy and immunomodulators such as levamizol, interleukins or interferons, and possibly monoclonal antibodies, are now being actively tested; the results are not yet conclusive.

Antibodies, Monoclonal↗
PubMed1987

[Termination rules in therapeutic trials. Application of sequential methods in 2 clinical trials in hematology].

In haematology, randomized clinical trials often use survival or disease-free interval as response criterion (censored data). For ethical reasons, interim analyses are usually performed, but these interim analyses lead to an increasing Type I error. Sequential methods allow for repeated testing. Three sequential methods are well-adapted to censored data: group sequential analysis, the sequential probability ratio test and the triangular test. The triangular test has the best properties: it allows an early termination of the trial whatever the difference between the treatment groups and without the risk of long duration trials. Sequential analyses can be performed at the same frequency as the usual interim analyses. These three sequential procedures have been applied to the analysis of two cooperative trials in haematology. It appears that the use of sequential methods has to be recommended in the design of randomized clinical trials with a censored response criterion.

Antibiotics, Antineoplastic↗
PubMed1987

[Use of prognostic knowledge in the planning and analysis of randomized therapeutic trials].

For most diseases, one observes great variability in clinical course and response to therapy which should be taken into account in the design and the analysis of clinical trials. Eligibility criteria and stratified randomization use prognostic knowledge. A suitable analysis of randomized studies includes: (1) checking treatment effect groups for comparability, (2) adjustment of treatment effect by stratifying or modeling to account for any imbalances in prognostic factors and to increase the precision of the treatment comparison by reducing random variation, (3) looking for treatment-covariate interactions suggesting that response to treatment depends on patients' characteristics. Tests for interaction should be interpreted with caution in light of medical plausibility; multiple comparisons should be taken into account. Recording information on known prognostic factors in clinical trials is important, as is the continuing search for new ones.

Clinical Trials as Topic↗
PubMed1987

Prevalence of magnesium and potassium deficiencies in the elderly.

Concentrations of magnesium and potassium in erythrocytes and plasma were determined in a population of 381 unselected elderly men and women, most of them in their eighties. The effects of biological factors (age, sex, weight) and a large set of pathological conditions, malignant or not, were examined. Analyses of variance showed a relation between age and concentrations of plasma potassium and between weight and concentrations of plasma magnesium. The chi-square test showed correlations between low concentrations of plasma magnesium and diabetes, abuse of alcohol and tobacco, and also between low values for erythrocyte magnesium and hypertension. Low values for plasma potassium were correlated with hypertension whereas high values were correlated with cardiovascular disease. Although some of the differences in the mean concentrations observed were statistically significant, these differences were always small. Most interesting was the distribution of the concentrations of the cations. This study shows that assays of both of these cations in erythrocytes were better than assays in plasma to evidence a deficiency. Indeed, about 20% of the studied population had low concentrations of both erythrocyte potassium and magnesium, whereas 2 and 10% had low values for plasma potassium and magnesium, respectively. This study underlines the large prevalence of magnesium and potassium deficiencies in the elderly, an observation we could not attribute to pathology or treatment. Routine electrolyte studies therefore appear to be justified in aged human subjects.

Age Factors↗
PubMed1986

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.

Adult↗
PubMed1986

[Biological aspects of chronic lymphoid leukemia].

The present study is concerned with clinical prognostic classifications of chronic lymphocytic leukemia derived from numerous statistics and multivariate survival analysis. We analyse the prognostic significance of some biological patterns: bone marrow histological studies, lymph node biopsies, size, structure and doubling time of blood lymphocytes, tumoral markers and karyotype analysis. The problem of the monoclonal clone origin is discussed: differentiation abnormality or proliferation of a physiological clone.

Female↗
PubMed1986

[Assessment of the quality of life of cancer patients. The preliminary applications to advanced bronchial cancers].

So far there is no good evidence that chemotherapy improves survival in non small cell lung cancer. Reports of randomized trials testing chemotherapy versus supportive treatment alone are very few. In recent years, more and more emphasis has been put on the quality of life for cancer patients. Subjective tests such as Anamnestic comparative self Assessment (A.C.S.A. test, Dr. Bernheim) were designed as well as objective ones, using different types of self evaluation. However very few studies have been focused on this aspect in patients with non small cell lung cancer. Therefore the G.E.T.C.B. (Groupe d'Etude et de Traitement des Cancers Bronchiques) decided to initiate a cooperative randomized trial (02 CB 84) in metastatic epidermoid and large cell bronchus carcinoma, in order to test the potential benefit from chemotherapy in these tumors and how it affects the quality of live. In this trial, C.O.P.A.C. combination (Cyclophosphamide, Vincristine, Cis-Platinum, Adriamycin and CCNU) is randomized versus no chemotherapy. The quality of life is assessed monthly on the one hand by a modified A.C.S.A. test performed by a physician and on the other hand by a question list given to the patient. This question list attempts to evaluate the impact of disease as a reference point. Finally protocol 02 CB 84 (activated in 05/84) may give information about the effect of chemotherapy on both survival and quality of life.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1986

[Application of sequential methods in randomized clinical trials with censored response criteria].

In randomized clinical trials with a censored response criterion, it is common practice to perform interim analyses, especially for reasons of medical ethics. Sequential methods allow for repeated testing. Three sequential methods are well adapted to censored data: the group sequential analysis, the sequential probability ratio test and the triangular test. Among them, the triangular test has the best statistical properties. The influence of the frequency of the analyses on the statistical properties of sequential methods has been studied by simulation: sequential analyses need not be performed more frequently than interim analyses. Sequential methods have been applied to several randomized clinical trials. The results are briefly reported for two of them. The ability of the triangular test and of the sequential probability ratio test to reach conclusions early when there is no difference between two compared treatments is supported by these two examples. Moreover, careful patient follow-up must be planned in the protocol in order to reduce the time for data updating and to perform sequential analyses at the required frequency. It appears well-founded to propose the use of the triangular test in randomized clinical trials with a censored response criterion. Four types of analyses with different aims must be planned in the protocol.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1986

[Long-term study of 416 cases of Parkinson disease. Prognostic factors and therapeutic implications].

As L-Dopa was marketed in France in 1971 for treatment of Parkinson's disease we used 1971 to divide a sample of patients into 2 groups. Group 1 (152 patients) includes patients with diagnosis made before 1971 and group 2 (264 patients) with diagnosis after 1971. The prognostic factors were motor deterioration, intellectual deterioration and death. The prognostic variables include the neuro-psychological status at the onset of the disease and at the beginning of L-Dopa treatment. The statistical analysis is based on Kaplan-Meier estimate, Log-rank test and Cox's model. In group 2, 10 years after the beginning treatment of L-Dopa, motor deterioration affected 60 p. 100 of the patients. The poor variables were akineto-hypertonic type, severe akinesia, poor clinical result after one year. Intellectual deterioration was frequent: 30 p. 100 at 10 years. The poor variables were age over 60, depression or psychotic episodes occurring during the first year. The 10 years-survival rate was 64 p. 100 and was not different from that recorded in a French population of same age and sex distribution. The poor variables were severe akinesia, presence of a Babinski sign, poor therapeutic result after one year, occurrence of psychotic episodes during the first year. The interval between the onset of the disease and the beginning of L-Dopa did not have any prognostic value, whatever the response criterion. In group 1, the same prognostic factors were pointed out. Survival and intellectual deterioration were not different in the 2 groups, but in group 1, motor deterioration appeared earlier.(ABSTRACT TRUNCATED AT 250 WORDS)

Follow-Up Studies↗
PubMed1985

Maintenance treatment of psoriasis by Tigason: a double-blind randomized clinical trial.

Extensive lesions on 36 patients with psoriasis were treated by Tigason, I mg/kg/day plus PUVA until skin clearance. A clinical score was calculated for each body area, and erythema, scaling, thickness and pruritus of the lesions were scored from 0 to 3. Skin clearing was defined as a clinical score less than 10% of the initial score. Double-blind maintenance treatment was then started. This was Tigason at half of the maximal dose tolerated during the clearing phase of the treatment v. placebo. Relapse of the disease was defined as the occurrence of a clinical score greater than 50% of the initial score. Among the 36 patients randomized, 20 received placebo and 16 received Tigason. Relapses increased quickly in the patients on placebo, but occurred in few patients treated by Tigason with 60% remaining clear after 1 year (P less than 0.05). Surprisingly, the kinetics of disappearance of the most frequent side effect, cheilitis, was the same in the Tigason group and in the placebo group. This double-blind randomized clinical trial shows that Tigason at low doses is an efficient and well-tolerated maintenance treatment of psoriasis.

Adult↗
PubMed1985

[Measles vaccination in the Sudan-Sahel region of Africa. Absence of the immunodepressive effect of malaria].

A survey aiming at assessing the effectiveness of anti-measles vaccination was carried out in a rural Upper-Volta population. The haemagglutination inhibition technique was used for detection of anti-measles antibodies; a reciprocal antibody titer of 20 or more was considered as a positive one and the subject considered as immunized. In the age group of 1-3 years old studied here, malaria does not seem to be a factor that modulates the ability of vaccinated subjects of producing anti-measles antibodies. Thus the immunodepressive properties of the Plasmodium is not observed in this immunizing system which effectiveness has been further improved by the development of thermostable vaccines.

Burkina Faso↗
PubMed1985

[Prevention of resistance to rifampicin by pyrazinamide in experimental tuberculosis in the mouse].

The capacity of Pyrazinamide (PZA) to prevent the selection of Rifampicin (RMP) resistant mutants was tested by the intravenous innoculation of 160 mice with 2 X 10(6) c.f.u. of M. tuberculosis, and two weeks later, the treatment of the mice either with 10 mg/kg/day RMP alone or with RMP + PZA 150 mg/kg/day. After three months of treatment, lungs and spleen were culture positive in respectively 95% and 90% of the mice treated with RMP alone and in 37% and 24% of the mice treated by RMP + PZA (p less than 10(-5). The strains isolated from lungs and spleen were resistant to Rifampicin in respectively 87% and 75% of the mice treated with RMP alone and in none of those treated with RMP + PZA.

Animals↗
PubMed1984

[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].

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.

Evaluation Studies as Topic↗