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Biomedical subjects

P Landais

Publications and source records attributed to P Landais.

At least 37 records · Page 2Linked to original sources
PubMed1999

The relation of putamen and caudate nucleus 18F-Dopa uptake to motor and cognitive performances in Parkinson's disease.

The contribution of striatal (caudate nucleus-putamen) dopaminergic deficiency to the severity of motor signs is well established in Parkinson's disease (PD), while its role in the occurrence of cognitive and mood changes remains unresolved. We therefore measured in 27 non-demented PD patients and 10 age-matched controls striatal uptake of [18F]-6-fluoro-L-Dopa (F-Dopa) with PET, and mood (Beck depression), memory (Grober-Buschke), frontal executive functions (verbal fluency and Wisconsin card sorting), and attentional processing of sensory stimuli (N2-P3 auditory event-related potentials--ERPs). Locomotor disability of patients was assessed by Hoehn and Yahr score and Unified Parkinson's Disease Rating Scale (UPDRS). ANOVA showed that memory, but neither frontal lobe functions nor ERPs, was significantly altered in PD patients, whereas indices of depression were found only in advanced PD. The F-Dopa rate constant Ki was significantly reduced in the striatum, more in putamen than caudate nucleus, and inversely correlated with disease duration. A significant inverse correlation was found between both putamen and caudate nucleus Ki and Hoehn and Yahr score, and between putamen--but not caudate nucleus Ki --and UPDRS motor score. Principal components analysis (PCA) of PD patients Ki values and mood, cognitive and ERP parameters gave a three-factor solution. Variables contributing to factor 1 were memory score and N2-P3 ERP latencies, those to factor 2 were striatal Ki values, and those to factor 3 frontal executive performances. Depression did not segregate with any variable. Our findings suggest that unlike locomotor disability, cognitive abilities and mood state of non-demented PD patients are for the most part unrelated to striatal dopaminergic depletion and may result from dysfunction of extra-striatal dopaminergic or from non-dopaminergic systems.

Adult↗
PubMed1999

Clinical and prognostic aspects of adrenocortical neoplasms in childhood.

BACKGROUND: A retrospective study of 54 children was undertaken to define the clinical presentation and secretory patterns of adrenal tumors and to evaluate the outcome of surgical resection and medical therapy. PROCEDURES: Different factors were studied in univariate and multivariate analysis by using the Cox proportional hazard model. RESULTS: Median age at diagnosis was 4 years. Boys and girls were affected equally. The disease was revealed by virilization (61%) or by a palpable mass (39%) with a 0.1-5.5 year delay from initial symptoms. At initial examination, we found that 76% of children were virilized. Ninety-four percent of the tested tumors secreted androgens, which were associated with glucocorticoids in 36%. Adrenal tumors in children were smaller than in adults. Half of them measured less than 10 cm. There were recurrences in 40% of children. The survival rate at 5 years was 49%, 70% if resection was microscopically complete and 7% if not (P < 0.001). CONCLUSIONS: In children, rare adrenal tumors have different diagnostic and prognostic characteristics than in adults; however, recurrences remain frequent. The efficacy of chemotherapy, mainly o,p'-DDD (Mitotane), remains to be evaluated in comparative trials.

Adolescent↗
PubMed1999

Influence of severe combined immunodeficiency phenotype on the outcome of HLA non-identical, T-cell-depleted bone marrow transplantation: a retrospective European survey from the European group for bone marrow transplantation and the european society for immunodeficiency.

We analyzed the outcomes of 214 HLA non-identical T-cell-depleted bone marrow transplantations (BMTs), performed in 178 consecutive patients for treatment of severe combined immunodeficiencies (SCID). Patients were treated in 18 European centers between 1981 and March 1995. SCID variants, that is, absence of T and B lymphocytes (B-) or absence of T cells with presence of B lymphocytes (B+) were found to have a major influence on outcome. The disease-free survival was significantly better for patients with B+ SCID (60%) as compared with patients with B- SCID (35%) (P =.002), with a median follow-up of 57 months and 52 months, respectively. Other factors associated with a poor prognosis were the presence of a lung infection before BMT (odds ratio = 2.47 [1.99-2.94]) and the use of monoclonal antibodies for T-cell depletion of the graft (odds ratio = 1.67 [1. 18-2.15]). Additional factors influencing outcome were age at BMT (<6 months) and period during which BMT was performed. Better results were achieved after 1991. Reduced survival of patients with B- SCID was associated with a higher incidence of early deaths from infection, a diminished rate of marrow engraftment, a trend to a higher incidence of chronic graft-versus-host disease, and slower kinetics of T/B immune function development. In both groups of patients, the use of busulfan (8 mg/kg total dose) and cyclophosphamide (200 mg/kg total dose) as a conditioning regimen provided the best cure rate (74% for patients with B+ SCID and 43% for patients with B- SCID, respectively), although results were not statistically significantly different from other regimens. This retrospective analysis should lead to the design of adapted measures to the performance of HLA non-identical BMT in patients with distinct SCID conditions.

Age Factors↗
PubMed1999

[Data collection about the case management of end-stage renal insufficiency. Feasibility study. Nephrology Epidemiologic and information Network (REIN)].

End-stage renal failure (ESRD) is an important public health issue, because of both the increasing number of patients requiring renal replacement therapy and the cost of treatment. The need for a reliable data system, capable of describing the patient care network as a whole, including dialysis or transplantation, has often been reiterated. The Direction Générale de la Santé (the French Department of Health) commissioned INSERM (the National Institute of Health and Medical Research) to "study the feasibility of different scenarios of data collection about ESRD patient care in order to meet the priority needs of health care administration, physicians, and researchers". Analysis of these needs allowed the goals to be defined: to provide an accurate picture of ESRD patient care in order to guide and evaluate health care policy, to inform clinicians, and to provide a tool for more focused special studies in renal research issues. Three scenarios were studied: the first would use data systems of both the government and the National Health Insurance system for planning health care services, upon EfG (The French Transplant Agency) network to evaluate transplantation, and upon a few regional registries for epidemiology and research; the second is based on repeated cross-sectional surveys; the third would rely upon the organization of an information system, the Renal Epidemiology and Information Network (REIN). Regional centers and a national coordinating office would register and follow-up ESRD patients, principally to evaluate health care supply and quality. The REIN database would also be a resource for research. The advantage of the first scenario is its low cost; its principal drawback is that evaluations will not be possible in the regions without registries. The second suggestion is inadequate. The last project would fulfil the goals that were defined. The REIN data system would be a true public health project of interest to all the participants and institutions in this field.

Case Management↗
PubMed1999

[A clinical study of chronic perennial and permanent rhino-sinusal dysfunction. II. Clinical pattern of different pathologies].

Following a univariate analysis of the clinical features of chronic perannual and permanent rhinosinus dysfunction, the aim of this work was to complete the study by a multivariate analysis. The analysis was based on the three main pathologies retained (chronic sinusitis, bilateral symmetrical pansinusitis, anterior facial sinusitis). Each pathological situation was divided into subgroups, Phadiatop positive or negative chronic rhinitis, bilateral symmetrical chronic panethmoiditis or stage I, II or III naso-sinus polyposis, maxillary sinusitis or anterior facial pansinusitis. The clinical features of these different entities were detailed (number, quality and laterality of the symptoms, results of the physical examination). This clinical description was compared with paraclinical findings, particularly computed tomography of the face.

Cerebrospinal Fluid Rhinorrhea↗
PubMed1998

Long-term immune reconstitution and outcome after HLA-nonidentical T-cell-depleted bone marrow transplantation for severe combined immunodeficiency: a European retrospective study of 116 patients.

We have performed a retrospective analysis of the development of T- and B-cell functions after HLA-nonidentical T-cell-depleted bone marrow transplantation (BMT) performed in 193 patients with severe combined immunodeficiency (SCID) at 18 European centers between December 1982 and December 31, 1993. One hundred sixteen of 193 patients were alive with evidence of engraftment 6 months after BMT. Development of T-cell function occurred earlier than B-cell function and was achieved more frequently up to the time of last follow-up. The median time to achieve normal T-cell function was 8.7 months, whereas the median time to achieve normal B-cell function was 14.9 months. Twenty-four patients died later than 6 months post-BMT, mainly due to chronic graft-versus-host disease (cGVHD) and/or viral infection. Absence of T-cell reconstitution 6 months after BMT, unlike absence of B-cell reconstitution, was associated with a poor outcome. Two additional factors were associated with a poor outcome: presence of cGVHD 6 months after BMT and B- SCID versus B+ SCID. However, two of these three factors remained as significant prognostic factors in a multivariate analysis: the absence of T-cell function and the presence of cGVHD 6 months after BMT. Analysis of the factors influencing the development of immune reconstitution showed that T- and B-cell functions occurred earlier and more frequently in B+ SCID versus B- SCID patients. Acute GVHD was associated with a slower development of T-cell function at 6 months, and cGVHD had a negative influence on the development of T-cell function afterwards, but neither acute nor chronic GVHD was found to influence the development of B-cell function. Once engraftment occurred, whether patients had or had not received Busulfan in the conditioning regimen did not influence the kinetics and quality of T-cell function development. In a multivariate study, two factors were found to influence the T-cell function 6 months after BMT: type of SCID and acute GVHD. The results of this retrospective analysis should lead to new protocols adapted to SCID disease, considering that disease-related as well as BMT-related parameters influence the development of immune function and thereby long-term outcome after HLA-nonidentical T-cell-depleted BMT.

B-Lymphocytes↗
PubMed1998

Harmful long-term impact of hepatitis C virus infection in kidney transplant recipients.

BACKGROUND: The long-term impact of hepatitis C virus (HCV) infection in renal transplant recipients remains controversial. We report here our experience, in a homogeneous single center, of 499 patients with a fairly long follow-up. METHODS: We retrospectively studied 499 hepatitis B virus-negative patients who received an initial cadaver donor kidney transplantation at Necker Hospital between January 1, 1979 and December 31, 1994, with a graft or patient survival of at least 6 months. Anti-HCV antibodies were detected at time of transplantation in 112 patients (22%). Patient survival and causes of death were compared among anti-HCV-positive and -negative patients RESULTS: Our results clearly indicate that first cadaver kidney transplant recipients with anti-HCV antibodies had a significantly shorter patient and graft long-term survival than recipients without anti-HCV antibodies (P<0.01 and P<0.0001 respectively). Mean follow-up time after transplantation was 79+/-2 months in the former group and 81+/-5 months in the latter (NS). Increased mortality was primarily caused by liver disease (P<0.001) and sepsis (P<0.01). In a multivariate analysis, HCV infection significantly affected the mortality rate (odds ratio: 2.8). CONCLUSIONS: These results suggest that HCV infection has a harmful long-term impact on the survival of kidney transplant recipients.

Adult↗
PubMed1998

Low dose linomide in Type I juvenile diabetes of recent onset: a randomised placebo-controlled double blind trial.

The quinoline-3-carboxamide, linomide, protects non-obese diabetic mice from diabetes. The effects of linomide on insulin needs and beta cell function were studied in recent juvenile Type I diabetes in a double-blind trial. Patients with recent onset diabetes were randomly assigned to treatment with a fixed dose of 2.5 mg linomide (42 patients) or placebo (21 patients) for 1 year, in addition to insulin and diet. Glycated haemoglobin was 10-15% lower at 9 months (p = 0.003) and 12 months (p < 0.05) in the linomide group. The insulin dose was 32-40% smaller in the linomide group at 3 (p < 0.03), 6 (p < 0.02), 9 (p < 0.001) and 12 months (p = 0.01). Insulin doses correlated negatively with C peptide values (p = 0.001-0.002). The trend for higher C peptide values in the linomide group did not reach significance. In a post hoc subgroup analysis performed in 40 patients (25 from the linomide group and 15 from the placebo group) who still had detectable residual beta cell function at entry, linomide was associated with 45-59% higher C peptide value at 6 months (p < 0.05), 9 months (p < 0.05) and 12 months (p < 0.05). The main adverse effects of linomide were mild transitory anaemia (45 vs 10% in the linomide and placebo groups), thrombocytopenia (24 vs 10%), and mild joint discomfort (45 vs 5%) with no clinical signs. In conclusion, low-dose linomide reduced the insulin needs in patients with juvenile Type I diabetes of recent onset and improved beta cell function in patients who still had detectable beta cell function at entry. These results support further clinical and experimental studies to define the effects of linomide in Type I diabetes provided the safety of linomide is reliably established.

Adjuvants, Immunologic↗
PubMed1998

[Principles of tests of hypotheses in statistics: alpha, beta and P].

Modern clinical research requires control of statistical methods. We reviewed 120 original manuscripts which were submitted to the Annales françaises d'anesthésie et de reanimation and analyzed their statistical methodology. Most of them contained errors (inappropriate numerical expression of the data, uncontrolled alpha risk, lack of power, use of inadequate statistical tests) and only 9 (7%) were considered as adequate. Therefore it is useful to come back to the methodology of hypothesis testing. An hypothesis test helps to decide between two hypothesis, the null hypothesis (H0) and the alternative hypotheses (H1) that we intend to demonstrate. The decision of the choice between H0 and H1 is associated with two probabilities: the alpha risk which is the probability to reject H0 whereas H0 is true, and the beta risk which is the probability not to reject H0 whereas H1 is true. Because the alpha risk is considered to be very important, it should be verified that the actual risk corresponds to the risk initially retained. The P value is the probability to observe a difference as great as that noted. The P value should be assessed according to its environment: the clinical relevance of a result should be assessed according to the amplitude of the difference and its confidence interval. When the null hypothesis is not rejected, the power of the test is essential. Power calculation is essential in clinical research trials. The number of patients included depends on four elements: the response to the control treatment, the expected response to the new treatment, the level of significance, and the power. The following items should be checked to choose the appropriate test: assess the kind of variable, verify the requirements for application of the test (type of the variable distribution, sample size, particular conditions such as equality of variance, dependence or independence of the variables), determine if data come from paired samples or if multiple comparisons are performed. Statistical analysis has become more easy with computers, however a precise knowledge of statistics remains essential. Advice from a statistician is often useful especially when obtained a priori and not a posteriori.

Analysis of Variance↗
PubMed1998

The effects of talking, reading, and silence on the "white coat" phenomenon in hypertensive patients.

To explore the mechanisms of the "white coat" phenomenon, the effects of talking, reading, and silence were analyzed. Fifty essential hypertensive patients were randomly allocated to periods of stress talking and relaxing reading, alternating with three periods of silence. While talking, systolic/diastolic blood pressure increased sharply, from 142 +/- 0.7/97.7 +/- 0.5 mm Hg to 159 +/- 0.7/111 +/- 0.5 mm Hg (P < .0001). While reading, systolic/diastolic blood pressure decreased (P < .0001). Moreover, talking and reading had opposite residual effects. The silence and reading periods gave the best approximations of the daytime ambulatory period. The predictive value of clinical blood pressure can be improved if measured during a period without talking, thus decreasing the "white coat" phenomenon.

Adult↗
PubMed1998

Diagnostic value of nasal provocation challenge with allergens in children.

A total of 106 children suffering from perennial rhinitis and/or asthma, and all allergic to Dermatophagoides pteronyssinus (DP), underwent nasal provocation challenge (NPC) with DP to determine the best method of diagnosis. Posterior rhinomanometry was uninterpretable in 17 patients and gave negative results in 31. Clinical scores for sneezing and rhinorrhea were more effective but did not diagnose the disorder in 11 children. However, nine of the 11 had significant increases in eosinophil count in the late phase. Clinical scores and cytology were also useful for assessing whether NPC with allergens was positive in children. The feasibility and safety of NPC with DP are high for rhinitic and stable asthmatic patients, but mild reactions may occur during the late phase.

Adolescent↗
PubMed1998

[Semiologic study of chronic perennial and permanent paranasal sinus dysfunction. Prevalence of symptoms].

Rhino-sinus dysfunction is associated with several symptoms: nasal obstruction, anterior and posterior rhinorrhea, episodes of sneezing, painful or heavy feeling in the face, taste and smell disorders. Certain manifestations have an impact on the pharynx, the larynx or the tracheobronchial tree. This prospective study was conducted in 449 consecutive patients who consulted over an 18-months period from November 1995 to May 1997. The objective was to determine the symptom pattern, main disease of the nasal cavities and paranasal sinuses which were involved: chronic rhinitis, anterior sinusitis, bilateral and symmetric pansinusitis with or without nasosinus polyps. In the first part of the study, the frequency of different symptoms were determined for the main nasosinus diseases. Statistical analysis of the correlations between symptoms and diseases provided a specific approach to symptoms.

Adolescent↗
PubMed1997

Statistical evaluation of hearing screening by distortion product otoacoustic emissions.

The aim of this study was to provide a statistical evaluation of the screening properties of distortion product otoacoustic emissions (DPOEs) in individuals with clinically normal hearing and in patients with pure sensorineural deafness of various degrees. The main informational parameters used were sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and the analysis of receiver operating characteristic (ROC) curves. For each frequency tested, ears were classified as a function of their audiometric threshold. Two groups were defined relative to an arbitrary reference, the "audiometric criterion." The PPV decreased and NPV increased with increases in the audiometric criterion. Each point of the ROC curve represents the relationship between the false alarm rate and the hit rate for each audiometric criterion ranging between 10 and 75 dB hearing level: the lower the audiometric criterion, the lower the hit rate value, and the lower the false alarm value. The audiometric criterion giving the highest hit rate and the lowest false alarm rate was 55 to 60 dB hearing level for primaries at 60 and 70 dB sound pressure level, or 25 to 30 dB hearing level for primaries at 30, 40, and 50 dB sound pressure level. These two different behaviors of ROC curves are consistent with the hypothesis that DPOEs do not represent activity at a single location along the basilar membrane.

Adolescent↗
PubMed1997

Circulating leptin in normal children and during the dynamic phase of juvenile obesity: relation to body fatness, energy metabolism, caloric intake, and sexual dimorphism.

In 112 obese compared with 42 lean children, we found that serum leptin is elevated early in the evolution of childhood-onset obesity (28.4 +/- 1.4 vs. 4.5 +/- 0.4 ng/ml in lean children, P < 0.0001) and correlates with adiposity. Obese children also had higher serum leptin normalized to fat mass. Despite high serum leptin, obese children ingested 2-3 times more calories than did lean control subjects (P < 0.0001) and gained weight rapidly (10.2 +/- 0.3 vs. 2.9 +/- 0.1 kg/year in control subjects, P < 0.0001). Girls had higher leptin levels than did boys, in obese as well as in nonobese children, and showed a closer correlation between adiposity and serum leptin. Elevation of serum leptin was comparable before and after puberty in obese boys, but puberty further increased leptin levels in obese girls (36 +/- 3 ng/ml), resulting in a clear sexual dimorphism with pubertal obese boys (22 +/- 5 ng/ml, P < 0.005). In conclusion, increased serum leptin reflects but does not halt fat deposition in childhood obesity. After normalization to body adiposity, leptin was found to be increased independently by obesity status, female sex, and female sexual maturation.

Blood Glucose↗
PubMed1997

Adaptation of the rectal wall to distension in children with constipation.

OBJECTIVE: To determine whether there is significant change in the tension-length relationship of the digestive smooth-muscle mechanical function in constipation in children and to examine a new method of analysis of the mechanical properties of the rectal wall. DESIGN: Case-control study. PARTICIPANTS: Thirty children with constipation and 30 control children who did not have constipation. INTERVENTION: Rapid distension of the rectal wall by inflation of a rectal balloon with air. MAIN OUTCOME MEASURES: The in vivo rectal pressure-volume P[t,V] curve was determined according to the quasilinear viscoelasticity law. The recorded pressure was defined as the product of 2 functions: the elastic response P0[V] and the reduced relaxation function G[t], a normalized function of time such that P[t,V] = P0[V] x G[t]. Analysis of variance with repeated measures and modelling (linear for P0[V] and exponential plus constant term for G[t] were used for data analysis. RESULTS: The quasilinear viscoelastic law can be applied to the in vivo determination of the mechanical properties of the rectal wall in controls and in children with constipation. The elastic response was similar in the 2 groups. The reduced relaxation function was significantly different between the 2 groups, with the absence of an asymptotic value in the group with constipation (p < 0.01). CONCLUSION: Distension of the rectal wall with the use of an air-inflated balloon, with this type of interpretation according to the viscoelastic law, is useful in the analysis of chronic constipation.

Adaptation, Physiological↗
PubMed1997

[Pefloxacin as a first-line treatment for nephrotic syndrome in minimal glomerular lesions in the adult. Multicenter study of 32 patients].

Minimal change nephrotic syndrome (MCNS) is the most frequent single cause of nephrotic syndrome occurring both in adults and children. Although it appears to be a self-limiting disorder (10% spontaneous remissions within the fortnight following the initial flare), MCNS displays a high rate of complications during the nephrotic period (10 to 15% cases) and prompts one to treat patients as early as possible. Corticosteroids are currently used as first-line treatment. A 16 weeks full-dose steroid course (1 mg/kg/day) usually induces remission in 75% MCNS in adults. Nevertheless, duration of treatment (9 months) and occurrence of relapses despite a slowly tapering dosage schedule, expose patients to steroids side-effects. Immunosuppressive drugs are recommended in case of steroid resistance and their side-effects are not harmless. Therefore, an alternative to steroids or immunosuppressives would lend a serious helping hand in MCNS management. The present work is dealing with pefloxacin efficacy in 40% MCNS in adults. Thirty-two MCNS adult patients were treated in a national multicenter study. A short-duration pefloxacin course (4 to 6 weeks) allowed partial or complete remission in 13 out of 32 cases. Thus far, this effect was undescribed for this class of drugs. Pefloxacin belongs to antibacterial agents of the fluoroquinolone family and is active against Gram negative Enterobacteria species. Fluoroquinolones also act on eukaryotic cells as lymphocytes and chondrocytes and alter IL2, gamma IFN and integrin expression. Although their precise mode of action is unknown in this kind of immunological disorder, fluoroquinolones might represent an alternative to steroids in some adult form of MCNS. However, predictive criteria for sensitivity to fluoroquinolones are currently not available and further controlled studies would be helpful using fluoroquinolones as first-line treatment in all the MCNS.

Adolescent↗
PubMed1996

Effects of two different crystalloid cardioplegic solutions assessed by myocardial pH, tissue lactate content and energy metabolism.

OBJECTIVE: The influence of composition of crystalloid cardioplegia is imprecise in clinical practice. Therefore, we investigated changes in intramyocardial pH, tissue lactate content and energy metabolism during cardioplegic arrest with 2 different crystalloid cardioplegic solutions. METHODS: Twenty patients were randomly allocated to 2 groups: 10 patients had crystalloid cardioplegia buffered with bicarbonate (neutral pH of 7.8 at 20 degrees) with no additives (St Thomas' II solution) and 10 patients had a non buffered crystalloid cardioplegia (mildly acidic pH of 7.4 at 20 degrees) enriched with glutamate and mannitol (Menasché's solution). Tissue lactate and energy metabolism were measured on myocardial biopsy specimens and intramyocardial pH were continuously measured during cardioplegic arrest by a miniature glass electrode. RESULTS: There were no statistical differences in hemodynamic results and in AMP, ADP, ATP, lactate values measured on biopsy specimens. The curves of intramyocardial pH were very similar in the 2 groups, the median values were 7.42 +/- 0.1 in group 1 and 7.41 +/- 0.1 in group 2 (temperature corrected values) and the areas under the curves were 260 +/- 4 and 259 +/- 4 in groups 1 and 2 respectively (P = NS). CONCLUSIONS: Glutamate provided no additive metabolic myocardial protection, bicarbonate had a weak buffering capacity in cold cardioplegic solutions and the 2 studied crystalloid solutions warranted a good myocardial protection in clinical practice.

Acid-Base Equilibrium↗