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Biomedical subjects

R Porcher

Publications and source records attributed to R Porcher.

At least 37 records · Page 2Linked to original sources
PubMed2003

Increase in bone mineral density of patients with spondyloarthropathy treated with anti-tumour necrosis factor alpha.

OBJECTIVE: To determine the changes in bone mineral density (BMD) in patients with spondyloarthropathy (SpA) treated with infliximab. PATIENTS AND METHODS: 29 patients (six women; 23 men) aged 22-68 years, with persistently active SpA despite a high dose of non-steroidal anti-inflammatory drug and/or treatment with methotrexate or sulfasalazine, were studied. Median duration of disease was 13 years (range 3-30). Twenty five patients were treated with 5 mg/kg and four with 3 mg/kg of infliximab at weeks 0, 2, 6 and then received either no infusion (n=3), or additional infusion of infliximab every other month (n=6), and the remainder received one infusion only in the case of a relapse. Lumbar and femoral BMD was measured by dual energy x ray absorptiometry at baseline and six months later. Serum osteocalcin and urinary deoxypyridinoline were measured in 19 patients at weeks 0, 2, 24, and in 13 patients at all visits. RESULTS: In six months there was a significant increase in BMD at the spine (3.6%, p=0.001), total hip (2.2%, p=0.0012), and trochanter (2.3%, p=0.0012). A trend for increase (1.1%) was observed at the femoral neck. There was an increase in osteocalcin between baseline and week 6 (third infusion)-median 1.45 micro g/l (p=0.013). No change in marker of bone resorption was observed at the same time. There was no change in biochemical markers between baseline and final visits. There was a trend for a correlation between the decrease at six months in erythrocyte sedimentation rate, and lumbar spine BMD change (r(s)=-0.35, p=0.06). CONCLUSION: These data suggest that a benefit of anti-tumour necrosis factor alpha therapy on BMD in patients with SpA may be through an uncoupling effect on bone cells.

Absorptiometry, Photon↗
PubMed2002

Ultrasonic characterization of human cancellous bone using transmission and backscatter measurements: relationships to density and microstructure.

The present study was designed to evaluate the relationships between ultrasonic backscatter, density, and microarchitecture of cancellous bone. The slopes of the frequency-dependent attenuation coefficient (nBUA), ultrasound bone velocity (UBV), the frequency-averaged backscatter coefficient (BUB) were measured in 25 cylindrical cancellous bone cores. Bone mineral density (BMD) was determined using X-ray quantitative computed tomography. Microarchitecture was investigated with synchrotron radiation microtomography with an isotropic spatial resolution of 10 microm. Several microstructural parameters reflecting morphology, connectivity, and anisotropy of the specimens were derived from the reconstructed three-dimensional (3D) microarchitecture. The association of the ultrasonic variables with density and microarchitecture was assessed using simple and multivariate linear regression techniques. For all ultrasonic variables, a strong association was found with density (r = 0.84-0.90). We also found that, with the exception of connectivity, all microstructural parameters correlated significantly with density, with r values of 0.54-0.92. For most microstructural parameters there was a highly significant correlation with ultrasonic parameters (r = 0.33-0.91). However, the additional variance explained by microstructural parameters compared with the variance explained by BMD alone was small (Delta r(2) = 6% at best). In particular, no significant independent association was found between microstructure and backscatter coefficient (a microstructure-related ultrasonic parameter) after adjustment for density. The source for the unaccounted variance of quantitative ultrasound (QUS) parameters remains unknown.

Aged↗
PubMed2002

Evaluating high dose therapy in Multiple Myeloma: use of quality-adjusted survival analysis.

PURPOSE: To incorporate quality-of-life considerations in assessing high dose therapy (HDT) for patients with Multiple Myeloma (MM). PATIENTS AND METHODS: A quality-adjusted survival analysis. using the quality-adjusted time without symptoms or toxicity (Q-TWiST) method, was applied to two randomized clinical trials conducted in patients with MM which compared randomized assignment to HDT vs. conventional chemotherapy (CCT) alone (MAG91) or followed by HDT (MAG90). Treatment benefit in terms of mean Q-TWiST was assessed through threshold utility analyses, i.e., sensitivity analyses of the choice of the utility coefficients over all possible values of utility weights. RESULTS: In both trials, results slightly favored the first-line HDT group over the first-line CCT group, with an average gain in TWiST of about 5.5 months over the 58 month-median follow-up period (27.8 vs. 22.3 months, respectively) in the MAG90 trial and 5.8 months over the 56 month-median follow-up period (19.1 vs. 13.3 months, respectively) in the MAG91 trial. The utility threshold analyses revealed that the first-line HDT group had a statistically increased mean quality-of-life adjusted time compared to the other group for a broad range of utility coefficient values. CONCLUSION: The development of such understandable and intuitive measures of expressing the relative benefit of complex treatment strategies is expected to be used in clinical decision making in the near future.

Antineoplastic Agents↗
PubMed2002

A modified RT-PCR technique to screen for viral RNA in the semen of hepatitis C virus-positive men.

BACKGROUND: Our objective was to use an adapted RT-PCR technique to assess the presence of hepatitis C virus (HCV) in semen and also in different density gradient semen fractions collected from men with chronic viral hepatitis participating in an assisted reproduction programme. METHODS: This study included 50 semen samples from 35 HCV(+) men, with active viral replication assessed by RT-PCR, collected the day of oocyte retrieval and used for assisted reproduction. These samples were subjected to standard assisted reproduction sperm preparation conditions, using density-gradient centrifugation with 45 and 90% layers. Aliquots of semen, 45 and 90% fractions, and embryo culture media were frozen at -80 degrees C for subsequent virological analyses. All aliquots were tested with a commercially available HCV RNA assay, adapted for use with semen after a number of technical changes. This assay yielded a sensitivity of 50-100 HCV RNA copies/ml and strongly diminished the effect of seminal amplification inhibitors. RESULTS: HCV RNA was detected in 7/50 (14%) semen samples tested, 5/35 (14.3%) men. HCV RNA was found in only 1/50 45% fractions but never in the 90% fraction or embryo culture media. Sera from 3/5 men contained 3.19-7.40 x 10(5) IU/ml, while the two others had 4.5 and 11.7 x 10(6) IU/ml. However, HCV RNA was quantified at <600 IU/ml in the HCV(+) semen of these five patients. The ongoing pregnancy rate was of 20% (10/50) with one delivery at the time of the present report. No anti-HCV antibody was found in any of the women or the newborn. CONCLUSIONS: Although HCV is present at low concentrations in the semen of a few HCV(+) patients, no purified sperm fraction (i.e. 90% fraction) used in assisted reproduction was HCV(+) and no seroconversion was observed in the women and the newborn, thereby suggesting a very low risk of virus transmission. Nevertheless, because the presence of HCV in semen implies a possible risk of nosocomial contamination, safety regulations must be strictly applied in assisted reproduction laboratories.

Abortion, Spontaneous↗
PubMed2002

The role of HLA genes in familial spondyloarthropathy: a comprehensive study of 70 multiplex families.

OBJECTIVES: To investigate whether HLA alleles, other than HLA-B27, influence predisposition to spondyloarthropathy (SpA) in multiplex families. METHODS: Seventy French families with at least two affected SpA members were recruited. Patients, and their first degree relatives were typed for HLA-A, B, C, and DR, and extended HLA haplotypes were determined. The distribution of HLA-A, C, and DR alleles carried on HLA-B27+ haplotypes in SpA families was compared with the distribution of these alleles among HLA-B27+ haplotypes in the French general population. Contribution to SpA susceptibility of HLA-A, B, C, and DR alleles, other than HLA-B27, was tested by transmission disequilibrium test. The contribution of HLA alleles to specific presentation features of SpA was examined. RESULTS: Frequencies of HLA-A, C, and DR alleles carried on HLA-B27+ haplotypes from SpA families were comparable with those seen in the French population, except for DR13 which was overrepresented among patients (pcorr<0.001). Most interestingly, the HLA-DR4 allele was transmitted in excess to patients with SpA, independently of linkage to HLA-B27 (pcorr=0.05), and in a direction opposite to that for HLA-B27+ unaffected siblings (pcorr=0.01). Finally, the distribution of HLA alleles was not related to the presentation feature of SpA. CONCLUSION: HLA predisposition to familial SpA appears not to be limited to HLA-B27, but some HLA-DR alleles also have a significant influence. In particular, HLA-DR4 contributes significantly to a genetic predisposition to SpA, which may have implications in our understanding of SpA pathogenesis.

Adult↗
PubMed2001

Multicenter, randomized comparative trial of fludarabine and the combination of cyclophosphamide-doxorubicin-prednisone in 92 patients with Waldenström macroglobulinemia in first relapse or with primary refractory disease.

Few reports are available on the treatment of patients with Waldenström macroglobulinemia (WM) and primary or secondary resistance to alkylating-agent-based regimens. From December 1993 through December 1997, 92 patients with WM resistant to first-line therapy (42) or with first relapse (50) after alkylating-agent therapy were randomly assigned to receive fludarabine (25 mg/m(2) of body-surface area on days 1-5) or cyclophosphamide, doxorubicin (Adriamycin), and prednisone (CAP; 750 mg/m(2) cyclophosphamide and 25 mg/m(2) doxorubicin on day 1 and 40 mg/m(2) prednisone on days 1-5). The first end point evaluated was the response rate after 6 treatment courses. Forty-five patients received CAP and 45 received fludarabine. Two patients died before the first course of chemotherapy. No statistical differences were observed between the 2 treatment arms with respect to hematologic toxicity or infections. Mucositis and alopecia occurred significantly more often in patients treated with CAP. Partial responses were obtained in 14 patients (30%) treated with fludarabine and 5 patients (11%) treated with CAP (P =.019). Responses were more durable in patients treated with fludarabine (19 months versus 3 months), and the event-free survival rate was significantly higher in this group (P <.01). Forty-four patients died, 22 in the fludarabine group and 22 in the CAP group. There was no statistical difference in the median overall survival time in the 2 study arms. Fludarabine was thus more active than CAP in salvage therapy of WM and should be tested as first-line therapy in a randomized comparison with alkylating agents.

Adult↗
PubMed2001

Estimating Lyapunov exponents in biomedical time series.

Among nonlinear dynamical invariants, determination of the largest Lyapunov exponent is well suited to positive identification of chaos in observed time series. When analyzing the dynamics of biomedical series, such as an electro-encephalogram (EEG), model-based methods should be used. Moreover, in the absence of any well founded theoretical model, and because of unexplained variability in the data, candidate models must provide for a stochastic component. Here we use nonlinear autoregressive stochastic modeling to estimate the dominant Lyapunov exponent in an EEG series and compute confidence intervals from surrogate data. The results are found to differ from those of approaches which aim at deleting noise prior to analysis.

Algorithms↗
PubMed2001

Prognostic value of radionuclide angiography in patients with right ventricular arrhythmias.

BACKGROUND: The prognosis of patients with right ventricular (RV) arrhythmias remains uncertain. This study prospectively evaluated the prognostic value of RV and left ventricular (LV) involvement assessed by radionuclide angiography (RNA) as predictors for sudden death. METHODS AND RESULTS: Patients (n=188) with severe arrhythmias originating from the RV were followed up for a mean of 45+/-34 months. Data on clinical presentation, resting and stress ECG, signal-averaged ECG, 24-hour Holter monitoring, and programmed stimulation were collected along with RNA. Patients were classified as group I (n=82) with normal RNA or group II (n=106) with an abnormal RV suggestive of arrhythmogenic RV cardiomyopathy, classified as diffuse or localized disease, with or without associated LV abnormalities. During follow-up, 14 patients died suddenly, all in group II. None of the clinical and electrical data were predictive of death. An abnormal RNA study was a highly predictive factor for death (P<0.005), as well as the presence of LV abnormalities (P<0.01). CONCLUSIONS: The present study confirms that arrhythmogenic RV cardiomyopathy is a severe disease with a high risk for cardiac death. Evidence of RV abnormalities in patients presenting with RV arrhythmias is highly predictive for sudden death, as is its association with LV involvement.

Adolescent↗
PubMed2001

Identification of prognostic factors in 61 patients with posttransplantation lymphoproliferative disorders.

PURPOSE: Prognostic studies of posttransplantation lymphoproliferative disorders (PTLDs) are hindered by the small number of cases at each transplant center. We analyzed prognostic factors and long-term outcome according to clinical manifestations, pathologic features, and treatment and investigated the prognostic value of the non-Hodgkin's lymphoma International Prognostic Index (IPI) in 61 patients with PTLD. PATIENTS AND METHODS: We studied 61 patients in two institutions who developed PTLD and analyzed factors influencing the complete remission and survival rates. RESULTS: In univariate analysis, factors predictive of failure to achieve complete remission were performance status (PS) > or = (P =.0001) and nondetection of Epstein-Barr virus (EBV) in the tumor (P =.01). Only a negative link with PS > or = 2 was observed in multivariate analysis. In univariate analysis, factors predictive of lower survival were PS > or = 2, the number of sites (one v > one), primary CNS localization, T-cell origin, monoclonality, nondetection of EBV, and treatment with chemotherapy. The IPI failed to identify a patient subgroup with better survival and was less predictive of the response rate than was a specific index using two risk factors (PS and number of involved sites), which defined three groups of patients: low-risk patients whose median survival time has not yet been reached, intermediate-risk patients with a median survival time of 34 months, and high-risk patients with a median survival time of 1 month. CONCLUSION: PS and the number of involved sites defined three risk groups in our population. The value of these prognostic factors needs to be confirmed in larger cohorts of patients treated in prospective multicenter studies.

Adolescent↗
PubMed2001

Evaluating treatment strategies in chronic lymphocytic leukemia: use of quality-adjusted survival analysis.

To assess comparatively, in terms of quality-adjusted survival, three front-line treatments in patients with stage B- or C-chronic lymphocytic leukemia (CLL). To describe better and compare the survival after randomization of patients from the CLL90 trial that randomly compared ChOP (cyclophosphamide, doxorubicin, oncovin, prednisone), CAP (cyclophosphamide, doxorubicin, prednisone) and fludarabine in advanced CLL, we performed a quality-adjusted survival analysis. This consisted of defining four clinical states (toxicity, treatment free of toxicity, no treatment nor symptoms, relapse), then summing up the average times spent in each state weighted by utility coefficients that reflect relative value according to quality of life. The resulting quality-adjusted time without symptoms or toxicity (Q-TWIST) was compared between randomized groups, and sensitivity (threshold) analyses to the choice of utility coefficients was performed. Over 73 months after randomization, the fludarabine group gained a mean of 45 days of toxicity-free survival at CAP, and 61 days over ChOP. The mean TWIST was 27.05 months with CAP, 31.5 months with ChOP and 32.95 months with fludarabine. The threshold analyses showed that, whatever the utility weights, the mean Q-TWIST was always greater with ChOP or fludarabine as compared to CAP. Fludarabine was consistently a better treatment than ChOP, except in the unlikely case of high utility weights attributed to toxicity and low utility weights attributed to treatment. Nevertheless, from a clinical point of view, differences between ChOP and fludarabine were moderate or event slight (mean difference in TWIST of 1.45 months). We conclude that patients with advanced CLL have a moderate benefit in terms of Q-TWIST when treated with fludarabine over ChOP. These two treatments are always superior to CAP.

Aged↗
PubMed2001

Evaluating treatment strategies in advanced Waldenström macroglobulinemia: use of quality-adjusted survival analysis.

A randomized phase II multicenter clinical trial comparing the efficacy of fludarabine (FAMP) to that of the association of cyclophosphamide, doxorubicin and prednisone (CAP) in 92 patients with Waldenstrom's macroglobulinemia in first relapse or with primarily resistant disease, was conducted on the behalf of the 'Groupe Coopératif Macroglobulinémie'. The main analysis of this study failed to demonstrate a clear cut benefit of FAMP in terms of overall survival (OS), although a significant benefit in terms of time to disease progression and event-free survival (EFS) was noted. In this rare disorder, where few randomized trials have been conducted, we took advantage of this trial to assess treatment differences while integrating quality of life considerations. We thus performed a quality-adjusted survival analysis, using the quality-adjusted time without symptoms or toxicity (Q-TWiST) approach. Four health states differing in terms of quality of life (QoL) were defined, namely treatment-related toxicity, treatment free of toxicity, no treatment or symptoms, and relapse. The average time spent in these health states (TOX, CT, TWiST and REL, respectively) were then weighted by utility coefficients reflecting relative QoL value according to that of TWiST and summed up giving the so-called Q-TWiST. No difference was found between randomized groups in terms of mean CT. Mean TOX in the two groups were similarly close except when considering alopecia as a relevant toxic event. By contrast, mean TWiST was 5.9 months longer in the FAMP group than in the CAP group (P = 0.006). Unsurprisingly, given the absence of difference in OS but the difference in EFS in favor of the FAMP group, mean REL was increased by 6.8 months in the CAP group (P = 0.047). As a result, benefit of FAMP in terms of average Q-TWiST only relied on the value of the utility coefficient attributed to REL (U(REL)), with a significant benefit when UREL ranged from 0 to 0.28, ie in patients undergoing poor QoL after relapse, which is likely.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2001

Factors affecting lymphocyte subset reconstitution after either related or unrelated cord blood transplantation in children -- a Eurocord analysis.

Immune recovery after cord blood transplantation (CBT) is of concern owing to the low number of lymphocytes transferred with the graft and their immaturity. Risk factors influencing lymphocyte subset reconstitution related to disease, patient, donor and transplant were studied in 63 children (< 16 years), given either related (n = 14) or unrelated (n = 49) CBT for malignant (n = 33) or non-malignant diseases (n = 30). Only children with sustained myeloid engraftment were analysed. Absolute numbers of T (CD3(+), CD4(+), CD8(+)), B and natural killer (NK) cells were reported 2--3, 6, 9, 12 and 12--24 months after CBT. Median patient age was 4.0 years (0--15) and median follow-up was 23 months (1.7--61.0). Twenty-six patients received human leucocyte antigen (HLA)-matched CBT and 37 received HLA-mismatched CBT. The median number of nucleated cells (NCs) collected/recipient weight was 6.1 x 10(7)/kg. In this selected population, the estimate 2 year survival was 85%. Lymphocyte reconstitution (defined as the median time to reach the normal value of age-matched healthy children) was 3, 6 and 8 months for NK, B and CD8(+) cells, while it was 11.7 months for both CD3(+) and CD4(+) lymphocytes. In the multivariate analysis, factors favouring T-cell recovery were: related donor (P = 0.002); higher NCs/kg (P = 0.005) and recipient cytomegalovirus (CMV)-positive serology (P = 0.04). Presence of acute graft-versus-host disease (GVHD) delayed T-cell recovery (P = 0.04). To summarize, in children with sustained myeloid engraftment the concern that lymphocyte recovery after CBT could be delayed does not appear to be substantiated by our results.

Adolescent↗
PubMed2001

Vascular endothelial growth factor, platelet endothelial cell adhesion molecule-1 and vascular cell adhesion molecule-1 in the follicular fluid of patients undergoing IVF.

BACKGROUND: The aim of our study was to measure concentrations of vascular endothelial growth factor (VEGF), platelet endothelial cell adhesion molecule-1 (PECAM-1) CD31 and vascular cell adhesion molecules (VCAM-1) in the follicular fluid of women treated with assisted reproduction technology to determine whether these proteins might be outcome markers. METHODS: Follicular fluid was collected from 75 patients < or =40 years undergoing oocyte retrieval procedures at our tertiary hospital during 1997 and 1998: 50 with tubal disease, 12 with endometriosis, and 13 whose partners had been diagnosed with severe oligoasthenoteratozoospermia. This retrospective analysis considered age and information about treatment and outcome for all these women who had undergone fewer than three assisted reproduction attempts. RESULTS: Nineteen women became pregnant (defined by human chorionic gonadotrophin concentrations and embryonic cardiac activity 1 month after follicular aspiration); 56 did not. Women did not differ significantly in their follicular fluid concentrations of VEGF, sCD31 and VCAM-1 according to cause of infertility, or assisted reproduction outcome, or age. Follicular fluid concentrations of VEGF were significantly correlated with the number of gonadotrophin ampoules administered (P < 0.012), and follicular fluid concentrations of sVCAM-1 with the fertilization rate (P < 0.01). Follicular fluid concentrations of VEGF and sVCAM-1 were also correlated (P < 0.007). CONCLUSIONS: Our results do not suggest that VEGF, CD31, or sVCAM-1 in follicular fluid predict assisted reproduction outcome, especially among patients < or =40 years old. The correlation of a high fertilization rate and sVCAM-1 in follicular fluid suggests that sVCAM-1 might be a marker of fertilization.

Abortion, Spontaneous↗
PubMed2001

Hydroxyapatite-coated versus grit-blasted femoral stems. a prospective, randomised study using EBRA-FCA.

We have carried out a prospective, randomised study designed to compare the long-term stability of the stem of cementless femoral implants with differing surface configurations. A total of 50 hips (46 patients) was randomised into two groups, according to whether the medullary stem had been grit blasted (GB) or coated with hydroxyapatite (HA). Both femoral prostheses were of the same geometrical design. We used Ein Bild Roentgen Analyse femoral component analysis (EBRA-FCA) to assess the stability of the stem. The mean follow-up was for 8.66 years. The mean migration of the stem was 1.26 mm in the HA group compared with 2.57 mm in the GB group (Mann-Whitney U test, p = 0.04). A mixed model ANOVA showed that the development of subsidence was statistically different in the two groups during the first 24 months. After this subsidence increased in both groups with no difference between them. Our results indicate that, with the same design of stem, HA coating enhanced the stability of the femoral stem when compared with GB stems.

Adult↗
PubMed2001

Ultrasonic backscatter and transmission parameters at the os calcis in postmenopausal osteoporosis.

Ultrasound technology has emerged as a new tool in the assessment of osteoporosis. Ultrasound parameters usually are measured in transmission; there is a potential for the analysis of backscattered signals to provide information on bone microarchitecture. The aim of this study was to explore a new technological development of the method, adding backscatter coefficient to transmission parameters, and to examine the appropriate thresholds to identify postmenopausal osteoporotic women. We examined 210 postmenopausal women (including 60 with osteoporotic fractures) and 30 healthy premenopausal controls. They had lumbar spine and hip bone mineral density (BMD) measurement and quantitative ultrasound (QUS) evaluation at the os calcis, measured in transmission (broadband ultrasound attenuation [BUA], speed of sound [SOS], ratio of transit time [dt] to BUA [dt/BUA], and "strength" index [STI]) and reflexion (broadband ultrasound backscattering [BUB]). The standardized CVs (sCVs) were between 2.27 % and 3.40 % for QUS measured in transmission and 4.41% for BUB. The odds ratio (OR) for fracture discrimination adjusted for age was 2.77 for hip BMD and between 1.6 and 2.9 for QUS. After adjustment for hip BMD, ORs were still highly significant for SOS, STI, and dt/BUA. According to hip BMD T score, prevalence of osteoporosis in our population was 39%. To detect the same prevalence, T scores ranged between -0.95 and -1.42 for QUS. QUS parameters have adequate ability to discriminate osteoporotic patients from controls. The World Health Organization (WHO) threshold for diagnosis of osteoporosis does not apply to this technology. The clinical utility of BUB at the os calcis, in addition to usual ultrasound parameters, is not yet proven. However, BUB evaluation, which does not require two transducers and may be implemented in conventional reflection mode systems, warrants further studies.

Aging↗
PubMed2000

Declining autopsy rate in a French hospital: physician's attitudes to the autopsy and use of autopsy material in research publications.

CONTEXT: Autopsy rates have been declining throughout the world, although preservation of the autopsy is considered a fundamental principle of medical care. In France, the 1994 bioethics law requires physicians to inform relatives before performing an autopsy. OBJECTIVE: To analyze the following factors that potentially influence hospital autopsy rates: legal constraints, autopsy reporting times, opinions of physicians requesting autopsies and pathologists regarding the usefulness of autopsy in patient care, and use of autopsy material in research publications. DESIGN: Record of the annual numbers of deaths and autopsies during a 10-year period (1988-1997). Record of the delays for transmission of final autopsy report to the requesting physician. Questionnaire analyzing the possible factors influencing autopsy rate. Categorization of articles published by pathologists according to the use of autopsy material. SETTING: A 1000-bed, university teaching hospital in the Paris, France, area. PARTICIPANTS: Questionnaire addressed to physicians, head nurses, and mortuary staff. RESULTS: A total of 1454 autopsies were reviewed. The autopsy rate declined from 15.4% in 1988 to 3.7% in 1997. This decline was marked after 1994 and tended to be slower for neurologic indications than for other indications. The final report had not been communicated within 180 days in 620 (42.6%) of 1454 autopsies. Fifty-five of 105 respondents considered that the bioethics law was one cause of the recent decrease of autopsy rate. Considering the contribution of autopsy to medical research, 94 (81%) of 116 articles dealing with central nervous system but only 28 (6%) of 464 articles dealing with other organs used autopsy-derived material. CONCLUSIONS: The 1994 bioethics law seems to contribute to the decline of autopsy. Inadequate delays for communicating autopsy results are frequent. Except for neuropathologists, autopsy is a minor source of research material.

Attitude of Health Personnel↗
PubMed1999

Individual smallest detectable difference in bone mineral density measurements.

Bone mineral density (BMD) measurement is a major outcome measure in osteoporosis. The BMD changes observed must exceed the variability inherent in the measurement process to be considered related to disease progression. The objective of the study was to estimate short-term variability of BMD measurement and to propose a cut-off value for the smallest detectable BMD changes for an individual. To estimate the short-term variability, 70 healthy postmenopausal women aged 53 +/- 4 years (group 1) and 57 elderly osteoporotic postmenopausal women aged 80 +/- 6 years (group 2) had two repeated BMD measurements of the lumbar spine (L2-L4) and the proximal femur with dual-energy X-ray absorptiometry, with complete repositioning within 1 h. Cut-offs derived from short-term variability were either estimated from the coefficient of variation (CV) (which is a function of the measured value) or from the standard deviation (SD), and applied to 330 postmenopausal women (group 3) who had BMD measurements at baseline and 2 years later. The short-term intrasubject variability was greater at the lumbar spine in group 2 versus group 1 (0.0123 vs. 0.0059 g/cm2, p < 10-4), whereas it was not at the femoral neck (0.0098 vs. 0.0076 g/cm2, p = 0.28). There was no statistically significant correlation between short-term intrasubject variability (SD) and BMD as demonstrated with an analysis of covariance (p values ranging from 0.17 to 0.90). Cut-offs estimated with SD and CV were individually applied to group 3 patients. Using these two cut-offs, discrepancies in assessment of progression were observed in 1.7-8.6% of cases. Short-term BMD variability is constant in a wide range of BMD values. Consequently, to determine cut-off values for the smallest detectable differences in BMD at the individual level, precision errors should be based on SD (expressed in absolute units) rather than on CV (expressed in percentage).

Absorptiometry, Photon↗