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Biomedical subjects

C Chastang

Publications and source records attributed to C Chastang.

At least 235 records · Page 13Linked to original sources
PubMedDate not supplied

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.

Clinical Trials as Topic↗
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Critical discussion of the assessment of a three-stage prognostic classification for chronic lymphocytic leukemia.

A study of the prognosis of two series of chronic lymphocytic leukemia (CLL) patients (99 from a retrospective series and 196 from a prospective series) has led us to propose a three-stage classification (A, B, C), requiring only a clinical examination and a haemogram. For stage A patients (comprising 50% of the CLL patients), survival rates are similar to those in the French general population of the same age and sex; median survival time is six years for stage B patients (comprising 35% of CLL) and two years for stage C patients (comprising 15%). Several methodological difficulties were encountered with the data and the statistical strategy, and these are discussed. The staging system has been justified, since the results have now been confirmed in four other series, totalling 611 CLL patients.

Bone Marrow↗
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A simulation study of three sequential methods for the comparison of two treatment groups when the response criterion is censored.

Three recent sequential methods, group sequential analysis (GSA), the sequential probability ratio test (SPRT) and the triangular test (TT) are well suited to randomized clinical trials with a censored response criterion, as they do not require matched pairs of patients. We undertook a simulation study to investigate their statistical properties and to compare these three methods with the fixed-sample design. Our results suggest that the three methods have the expected statistical properties for size and power; they allow an important reduction of the average number of events before stopping, except with GSA when there is no treatment difference; the triangular test (closed design) appears the optimal design, as the variance of the number of events is smaller than with the sequential probability ratio test (open design) and analysis after every twenty new events does not alter the statistical properties of these sequential methods and enhances their usefulness.

Biometry↗
PubMedDate not supplied

Patient accrual and interim statistical analysis in long-term randomized clinical trials: the French chronic lymphocytic leukemia CLL 80 protocol as a case study.

The CLL 80 clinical trial of treatment for chronic lymphocytic leukemia was designed using a three-stage prognostic classification. Within each stage patients received one of two treatments allocated by randomization, two adjacent stages having a common treatment. The fixed-sample design required 850 patients entered over a period of 8.5 years. Active patient recruitment led to 741 patients being randomized in four years. The first interim analysis, carried out at this point, showed a treatment difference in one stage which was statistically significant (p = 0.001) and justified an early termination of the protocol. This paper discusses practical aspects of patient accrual and interim analysis in this study.

Antineoplastic Combined Chemotherapy Protocols↗
PubMedDate not supplied

A transient state model for analysing ventilatory status in a randomized clinical trial.

We designed a randomized clinical trial to determine the efficacy of plasma exchange in Guillain-Barré syndrome, an acute neurological disease leading to paralysis in previously healthy subjects. Some patients require temporary mechanical ventilation during the course of the disease. Ventilatory status was analysed using a three-state model with a transient state defined by use of temporary mechanical ventilation, and the probability of being mechanically ventilated modelled as a function of time since randomization. The plot of this function reflects the effect of plasma exchange on ventilatory status showing that fewer plasma-exchanged patients than controls required ventilatory assistance and that the duration of assistance was shorter. Similar functions can be used in a more general framework when the response criterion includes a transient state.

Clinical Trials as Topic↗
PubMedDate not supplied

Designing a study for evaluating a protocol for the selective performance of preoperative tests.

Some basic concepts concerning classification of studies evaluating diagnostic procedures are given. The specific problem of assessment of routine preoperative tests is discussed: actual knowledge and methodological criticisms of previous studies, hypothesis for further evaluations, difficulties in the choice of a design and realization of a clinical study to assess a protocol for selective ordering of preoperative tests during one year in a teaching hospital. 3866 consecutive patients were included. The protocol led to perform only 33 per cent of all potential tests and did not apparently produce major adverse effects on the quality of care as appreciated by a clinical decision analysis.

Clinical Trials as Topic↗
PubMedDate not supplied

Lymph node involvement as the only prognostic factor in curative resected gastric carcinoma: a multivariate analysis.

The aim of this study was to evaluate the independent influence of clinical and pathological variables on survival of patients with gastric carcinoma using the Cox regression proportional hazard model. Of 156 patients operated on for gastric carcinoma, 46 (29.5%) underwent palliative operation, 24 (15.5%) had a palliative resection, and 86 (55%) had a curative resection. The overall 5-year survival rate was 25 +/- 4%. After curative resection, the 5-year survival rate was 44 +/- 6%. Univariate analysis applied to these patients showed that poor survival was related (p less than 0.01) to: age (over 80 years), absence of epigastric pain, vomiting and dysphagia, total gastrectomy, tumor size (more than 4 cm), lymph node involvement (LNI), invasion through the muscularis propria, absence of intestinal metaplasia near the tumor, and linitis plastica. In multivariate analysis, lymph node involvement was found to be the only independent prognostic factor. The 5-year survival rate was 75.5 +/- 8% without LNI, 28 +/- 10% with proximal LNI, and 7 +/- 6% with distal LNI. Our results suggest that classification into 3 LNI groups is the best staging system for curative resection in gastric carcinoma.

Adenocarcinoma↗
PubMedDate not supplied

A randomized comparison of two clarithromycin doses for treatment of Mycobacterium avium complex infections.

Two dosages of clarithromycin were compared for treatment of disseminated Mycobacterium avium disease of AIDS patients: high-dose (HD): 1,000 mg or 750 mg b.i.d. according to body weight, and low-dose (LD): 1,000 mg or 750 mg q.d. Patients with high probability of M. avium positive blood culture on day 0 received a 42-day clarithromycin treatment with HD (n = 27) or LD (n = 28) at random after stratification according to body weight. Assessment procedures, including quantitative blood cultures, were performed at days 14, 28 and 42. Forty-five patients were eligible for clinical and 28 for bacteriological evaluation. Bacteriological success was observed in 12 HD and 11 LD patients, partial success in one HD and two LD and failure in none of the HD and two LD (p = 0.33). Between days 0 and 42, log decreases in CFU counts/ml were (mean +/- SD) 3.13 +/- 0.82 (HD) and 2.67 +/- 1.8 (LD) (p = 0.38). Fever and night sweats significantly improved similarly in both groups; no change in spleen and liver size was observed on CT scans. Eight patients died during the study but no death was reported as drug related. Sixteen patients (HD = 6, LD = 10) discontinued the treatment because of side effects. A trend towards improved bacteriological effectiveness and reduced tolerance was observed in the HD group but the difference was not significant. With a power of 0.70, no dose effect was demonstrated between the two tested dosages. A daily dose of 1,000 mg clarithromycin was tested in drug combinations to treat disseminated M. avium infection in AIDS patients.

Adolescent↗
PubMedDate not supplied

Controlled study of malathion and d-phenothrin lotions for Pediculus humanus var capitis-infested schoolchildren.

Anecdotal reports have suggested that reduced efficacy of pediculicides against Pediculus humanus capitis could be related to resistance to treatments. Ovicidal and pediculicidal activities of 0.5% malathion and 0.3% d-phenothrin lotions were tested in an experimental model of P humanus capitis grown on rabbits to ensure that the two treatments were pharmacologically equipotent. We then did a randomised controlled trial in which the lotions were administered to 193 P humanus capitis-infested schoolchildren (malathion, 95; d-phenothrin, 98). Success rate was defined as the absence of both live lice and viable nits. Before treatment, live lice were collected and subjected to a pediculicidal test. Pharmacological tests showed 100% killing of the rabbit-grown nits and lice after exposure to both pediculicides. On day 1 of the controlled trial, the success rate was 92% in the malathion group (95% CI, 0.86-0.97) and 40% in the d-phenothrin group (0.30-0.49) (p < 0.0001); on day 7, it was 95% in the malathion group (0.90-0.99) and 39% in the d-phenothrin group (0.29-0.48, p < 0.0001). Malathion was also significantly more active in the pediculicidal tests compared to d-phenothrin and control. These results suggest an acquired resistance to d-phenothrin in the schoolchildren tested, since all other conditions of the administration of insecticides were standardised.

Animals↗
PubMedDate not supplied

[Guillain-Barré syndrome. Recent clinical and therapeutic aspects].

Guillain-Barré syndrome is an acute primary polyradiculoneuritis. A prototype of demyelinating disease, its essential characteristic is that it spontaneously evolves towards recovery from paralysis. Yet the vital and functional prognosis may be compromised in severe cases. Death and motor sequelae are particularly to be feared when the maximum deficit is severe and the maximum paralysis phase is prolonged. Cardiovascular vegetative disorders are also more frequent in these extended types. Symptomatic treatment rests on close supervision of the patients during the paralysis extension phase. Transferring the patient to an intensive care unit is mandatory as soon as disorders of deglutition and/or a significant decrease of vital capacity appear. Plasma exchange is the only treatment proven to be effective. It must be carried out early on in patients whose deficit is severe enough to interfere with walking and for whom this treatment is not contra-indicated. Fresh frozen plasma must not be used as replacement solution: it creates more incidents and complications than diluted albumin and has no additional beneficial effect on the course of the neurological disease.

Humans↗
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Peripheral stem cells in bone marrow transplantation. Cord blood stem cell transplantation.

Since it was shown that the number of haematopoietic stem cells contained in one sample of cord blood was sufficient for engrafting children and adults, cord blood banking has developed world wide. Cord blood banking has several advantages, including availability of this source of stem cells, low viral infection rate at birth, speed of the search and the possibility of collecting cord blood in ethnic groups under-represented in bone marrow donor registries. Other possible advantages which require further study, include a low risk of acute graft-versus-host disease, even with some degree of HLA mismatch. More than 700 cord blood transplants have been reported worldwide. The Eurocord Registry has analysed 250 cases. Briefly, analysis of the clinical results has shown that related cord blood transplants give better results than unrelated cord blood transplants. Factors associated with better survival in related and unrelated transplants were younger age, diagnosis with better results in inborn errors and children with acute leukaemia in first or second remission. High number of nucleated cells in the transplant and recipient negative cytomegalovirus serology were also favourable risk factors for survival.

Adult↗
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Incidence and causes of carbon monoxide intoxication: results of an epidemiologic survey in a French department.

The purpose of this study was to estimate the incidence, mortality, and causes of carbon monoxide intoxications in France. A survey was conducted in the department of the Hauts-de-Seine, which is representative of the French population. Data were collected through a headquarters that had direct contact with all department emergency organizations and to a technical laboratory. During the 3-y study, 735 cases that were related to 291 events were reported. Thirty-six patients died. The average incidence of carbon monoxide intoxications was 17.5 per 100,000 inhabitants. Poisoning was caused by fires in 36 events and by car exhausts in 12. For the remaining events, causes were determined as follows for 196: water heaters (57%), boiler (20.5%), coal stove (9%), brazier (4%), cooker (2%), heating device (1.5%), and miscellaneous (6%). The main mechanisms of intoxication were a defective device, poor ventilation, or poor evacuation of combustion gases. Carbon monoxide intoxication occurs frequently in France, and preventive actions are warranted.

Animals↗
PubMedDate not supplied

Male urethritis with and without discharge: a clinical and microbiological study.

BACKGROUND: The definition of male urethritis in the absence of urethral discharge has not been well established. The sensitivity of urethral swabs and first-catch urine is controversial. GOAL OF THIS STUDY: To correlate clinical data (discharge or not), urethral swabs, and first-catch urine examinations with the microorganisms found within the urethra in a cohort of men attending the sexually transmitted disease clinic of Hôpital Saint Louis (Paris) for treatment of urethral symptoms with or without discharge. STUDY DESIGN: Two-hundred-seventy-three consecutive male patients entered this prospective study between October 1, 1992 and November 30, 1992. Fifty-two patients were excluded because they had been treated with antibiotics in the previous 3 months. All patients were screened for Chlamydia trachomatis, Neisseria gonorrhoeae, Mycoplasma genitalium, Trichomonas vaginalis, Ureaplasma urealyticum, Mycoplasma hominis, and Candida albicans. RESULTS: Two-hundred-nineteen patients were eligible for the study (122 with discharge and 97 with no discharge). The prevalence of microorganisms was as follows: Chlamydia trachomatis in 13%, Neisseria gonorrhoeae in 11%, Ureaplasma urealyticum in 7%, Mycoplasma genitalium in 17%, Trichomonas vaginalis in 1%, and indeterminate pathogens alone in 20%. All major pathogens and Mycoplasma genitalium were more common in patients with discharge. Stratification of results according to the presence of polymorphonuclear leukocytes on the urethral swab and first-catch urine showed a low sensitivity of both tests for Chlamydia trachomatis (29%), Mycoplasma genitalium (50% and 62%), and Ureaplasma urealyticum (33%) in patients with no discharge. CONCLUSION: A specific and sensitive search for Chlamydia trachomatis should be done in every patient with urethral symptoms whether or not the classic symptoms of urethritis are present (discharge, presence of polymorphonuclear leukocytes in the urethra or first-catch urine).

Adult↗