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Biomedical subjects

A Lallemand

Publications and source records attributed to A Lallemand.

At least 19 recordsLinked to original sources
PubMed2004

Lipoma arborescens of the knee: report of a case managed by arthroscopic synovectomy.

We report a case of lipoma arborescens treated with an arthroscopic procedure. Lipoma arborescens is an uncommon pseudo-tumoral synovial lesion usually located in the suprapatellar pouch of the knee. This diagnosis should be considered, particularly in patients with chronic joint effusion. Magnetic resonance imaging confirms the lipomatous nature of the synovial proliferation. When limited to the anterior compartment of the knee, lipoma arborescens can be treated by arthroscopic synovectomy.

Adipose Tissue↗
PubMed2003

Autofluorescence spectroscopy of malpighian epithelial cells, as a new tool for analysis of cervical cancer precursors.

A spectroscopic analysis of autofluorescence was investigated within the cell cytoplasm from cervical malpighian epithelia prepared on Thin-Prep smears. Autofluorescence emission spectra from 22 cervix were analyzed by microspectrofluorometry under a 363 nm laser excitation. Among the analyzed cervix, 6 were in normal limits, 6 in inflammatory limits, 5 were evocative of Low-Grade Squamous Intraepithelial Lesions (LGSILs) and 5 were evocative of High-Grade Squamous Intraepithelial Lesions (HGSILs). Cytoplasmic emission intensities at 450 nm of cells from inflammatory, LGSIL and HGSIL cervix were equivalent and were 3-fold higher than from normal cervix. All smears presented a two-fold lower autofluorescence emission in the cytoplasm than in the nucleus. The spectral profile analysis allows the discrimination of cells from inflammatory, LGSIL and HGSIL cervix. The 525/425 nm emission ratios were 0.75+/-0.1, 0.96+/-0.04 and 1.2+/-0.1 for inflammatory, LGSIL and HGSIL, respectively. We suggest that smears of normal, inflammatory, LGSIL and HGSIL cervix could be discriminated by the analysis of the 450 nm emission intensity and 525/425 nm emission ratios from cells of malpighian epithelia.

Adult↗
PubMed2001

Distribution of gacyclidine enantiomers after experimental spinal cord injury in rats: possible involvement of an active transport system.

The pharmacokinetics of gacyclidine enantiomers, a noncompetitive N-methyl-D-aspartate (NMDA) antagonist, were studied in plasma and spinal cord extracellular fluid (ECF) after experimental spinal cord injury in rats. Spinal cord trauma was produced by introducing an inflatable balloon in the dorsal subdural space. Upon implantation of microdialysis probes in spinal cord (T9) and intravenous (iv) bolus administration of (+/-)-gacyclidine (2.5 mg/kg), concentrations in plasma and ECF were monitored over 5 h and analyzed by a stereospecific gas chromatography-mass spectrometry (GC-MS) assay. In plasma, concentrations of (+)-gacyclidine were approximately 25% higher than those of (-)-gacyclidine over the duration of the experiment and decayed in parallel (t(1/2 alpha) approximately 7 min; t(1/2 beta) approximately 90 min) with no significant difference between the two enantiomers. Clearance (CL) and volume of distribution (Vd) of (-)-gacyclidine were approximately 20% higher than those of its optical antipode (CL: 285 versus 236 mL. kg(-1). min(-1); Vd(beta): 39.3 versus 31.2 l/kg). Protein binding (approximately 91%) was not stereoselective. In spinal cord ECF, both enantiomers were quantifiable within 10 min after drug administration, and their concentration remained stable over the duration of the experiment in spite of changing blood concentrations. Repeated iv bolus injections of gacyclidine did not modify these profiles. Areas under the curves (AUCs) of concentration in ECF versus time were similar for both enantiomers and not correlated with AUCs in plasma. Penetration of (-)-gacyclidine was, however, significantly higher (approximately 30%) than that of (+)-gacyclidine. In summary, the disposition of gacyclidine enantiomers is stereoselective. Both enantiomers exhibit a high affinity for spinal cord tissue, and the drug exchange between plasma and spinal cord ECF involves an active transport system. These findings contribute to the explanation of the discrepancy between drug concentrations in plasma and spinal cord ECF.

Animals↗
PubMed2001

Comparison between two models of cooling surfaces using blowing.

To protect surfaces against high temperatures, the blowing through a porous material is studied. The geometry is that of a circular cylinder in cross-flow and the effectiveness of the blowing for the thermal protection is numerically investigated. Two models are developed for the blowing simulation and comparisons are made with experimental data obtained in a heated wind-tunnel. It is shown that the blowing strongly affects the dynamical and thermal profiles over the surface, thickening the boundary layers and decreasing the external transfer coefficients. It results in a lower viscous drag and thermal stress. The wall temperature dramatically decreases with blowing and the heat flux is also affected.

Journal Article↗
PubMed2000

Influence of schedule of administration on methotrexate penetration in brain tumours.

The influence of the administration schedule (intravenous (i.v.) bolus versus i.v. infusion) on the pharmacokinetics of methotrexate (MTX) in plasma and extracellular fluid (ECF) of a brain C6-glioma was investigated in rats. MTX concentrations were determined by high performance liquid chromatography (HPLC)-ultraviolet radiation (UV). MTX (50 mg/kg) was administered by i.v. bolus or i.v. infusion (4 h). Concentration-time profiles were fitted to a two-compartment open model. Maximum MTX concentrations ranged between 178 and 294 microgram/ml (i.v. bolus), and between 11 and 24 microgram/ml (i.v. infusion) in plasma. MTX rapidly entered the tumour tissue although its concentrations in the ECF were much lower than those observed in plasma for both modes of administration. In spite of an important interindividual variability, AUC(ECF) was approximately 5-fold higher and mean MTX penetration in tumour ECF (AUC(ECF)/AUC(Plasma)) was approximately 3-fold higher after i.v. bolus than after i.v. infusion administration. These results indicate that i.v. bolus administration schedules promote MTX delivery in brain tumour tissue.

Animals↗
PubMed2000

Distribution of gacyclidine enantiomers in spinal cord extracellular fluid.

PURPOSE: Determination of the pharmacokinetics of gacyclidine enantiomers, a non-competitive NMDA antagonist, in plasma and spinal cord extracellular fluid (ECF) of rats. METHODS: Implantation of microdialysis probes in spinal cord (T9). Serial collection of plasma samples and ECF dialysates over 5 hours after IV bolus administration of (+/-)-gacyclidine (2.5 mg/kg). Plasma protein binding determined in vivo by equilibrium dialysis. Chiral GC/ MS assay. RESULTS: Plasma concentrations of (+)-gacyclidine were approximately 25% higher than those of (-)-gacyclidine over the duration of the experiment in all animals. Plasma concentrations decayed in parallel in a biphasic manner (t1/2alpha approximately 9 min; t1/2beta approximately 90 min) with no significant difference between enantiomers. Clearance and volume of distribution of (-)-gacyclidine were approximately 20% higher than those of its optical antipode (CL: 248 vs 197 ml.kg(-1)x min(-1); Vdbeta: 31.6 vs 23.5 1/kg). Protein binding (approximately 90%) was not stereoselective. Both gacyclidine enantiomers were quantifiable in spinal cord ECF 10 min after drug administration and remained stable over the duration of the experiment in spite of changing blood concentrations. Penetration of (-)-gacyclidine was significantly higher (approximately 40%) than that of (+)-gacyclidine in all animals. Yet, exposure of spinal cord ECF was similar for both enantiomers, and not correlated with plasma AUCs. CONCLUSIONS: The disposition of gacyclidine enantiomers is stereoselective. Both enantiomers exhibit a high affinity for spinal cord tissue and their distribution may involve a stereoselective and active transport system. This hypothesis could also explain the discrepancy between drug concentrations in plasma and spinal cord ECE

Animals↗
PubMed1999

Pharmacokinetics of methotrexate in the extracellular fluid of brain C6-glioma after intravenous infusion in rats.

PURPOSE: Establishment of the pharmacokinetic profile of methotrexate (MTX) in the extracellular fluid (ECF) of a brain C6-glioma in rats. METHODS: Serial collection of plasma samples and ECF dialysates after i.v. infusion of MTX (50 or 100 mg/kg) for 4 h. HPLC assay. RESULTS: Histological studies revealed the presence of inflammation, edema, necrosis, and hemorrhage in most animals. In vivo recovery (reverse dialysis) was 10.8 +/- 5.3%. MTX concentrations in tumor ECF represented about 1-2% of the plasma concentrations. Rapid equilibration between MTX levels in brain tumor ECF and plasma. ECF concentrations almost reached steady-state by the end of the infusion (4 h), then decayed in parallel with those in plasma. Doubling of the dose did not modify MTX pharmacokinetic parameters (t1/2alpha, t1/2beta, MRT, fb, Vd, and CL(T)), except for a 1.7-fold increase of AUC(Plasma) and a 3.8-fold increase in AUC(ECF), which resulted in a 2.3-fold increase in penetration (AUC(ECF)/AUC(Plasma)). In spite of an important interindividual variability, a relationship between MTX concentrations in plasma and tumor ECF could be established from mean pharmacokinetic parameters. CONCLUSIONS: High plasma concentrations promote the penetration of MTX into brain tissue. However, free MTX concentrations in tumor ECF remain difficult to predict consistently.

Animals↗
PubMed1998

Neonatal hip: from anatomy to cost-effective sonography.

Therapeutic success in treating congenital dysplasia of the hip is associated with early diagnosis, but the specific neonatal anatomy makes screening difficult. The purpose of this study was to determine whether this specific neonatal anatomy is taken into account by current ultrasound (US) techniques. Anatomic studies were performed on 22 hips, US examinations on 7750 neonatal hips; 2370 untreated hips were reexamined at 1 month by US and at 3 months by X-ray. The transformation of the neonatal cartilaginous acetabulum into an osseous cavity is dependent on harmonious metaphyseal growth and a properly seated femoral head. Defects in the acetabular roof, together with displacement of the femoral head, cause an abnormal anatomical relationship which leads to further deformities. The described sonographic techniques give only partial information on these specific abnormalities. The sonographic monoplanar methods as used in Graf's technique, which relies largely on acetabular development, lead to difficulties in assessing posterior coverage of the femoral head and difficulties in assessing alignment of the metaphyseal weight-bearing surface with the femoral head. Combining Graf's morphological analysis with Novick's dynamic technique enables one to more accurately define the relationship of the femoral head and the acetabulum and increases the reliability and predictive value of the examination, while reducing the number of doubtful cases. This makes screening cost effective.

Cost-Benefit Analysis↗
PubMed1997

Anatomic study of the pre- and neonatal hip. Physiopathologic considerations on dysplasia and congenital dislocation of the hip.

Therapeutic success in dysplasia and congenital dislocation of the hip depends on an early diagnosis. The physiopathology remains very debatable and several concepts are propounded. For a better physiopathologic understanding, the authors have carried out a study of the morphology and development of 22 pre- and neonatal hips. At first, the acetabulum is cartilaginous and distorted by the moving femoral head; this acetabulum is histologically affected by the femoral pressure. The pathologic hip is characterized by defective posterior bony coverage of the femoral head by the acetabulum. The acetabulum ossifies during the 3 months following birth, forming a cup-like cavity under the pressure of the femoral head. Therefore, neonatal screening tests such as sonography must take place in the first weeks of life.

Acetabulum↗
PubMed1997

Normal vas deferens in fetuses with cystic fibrosis.

PURPOSE: Infertility in patients with cystic fibrosis has been attributed to the congenital bilateral absence of the vas deferens. We studied the vas deferens in cystic fibrosis fetuses to determine whether this condition could be related to primary developmental abnormalities or to secondary obstructions. MATERIALS AND METHODS: Two cystic fibrosis male fetuses, with deltaF508+/+ and deltaF508/G542X genetic mutations, were examined after abortion at 12 and 18 weeks, respectively. The lumens of the vas deferens were measured using histological serial sections in the 2 cystic fibrosis fetuses and in 6 control fetuses. RESULTS: The vas deferens of cystic fibrosis and control fetuses showed a similar development. The diameters of the lumens were smaller at the extremities than in the medial part of the duct in cystic fibrosis and in control fetuses. No epithelial necrosis, focal dilatation or fibrous stenosis could be detected at any age. Secretions were observed in the lumen of the vas deferens of the homozygous fetus, but no obstruction was detected. CONCLUSIONS: The normal organogenesis of the vas deferens, the presence of secretions filling the lumen of the deltaF508 +/+ fetus and the high proportion of normal ducts reported in prepubertal male cystic fibrosis patients suggest a mechanism of luminal obstruction resulting in duct atrophy and infertility in male adults with cystic fibrosis. The term "atresia" or "inspissation" should be used in cases of congenital bilateral absence of the vas deferens associated with cystic fibrosis mutations, whereas the term "agenesis" should be used for cases of congenital bilateral absence of the vas deferens associated with urogenital abnormalities in which regional defects occur during organogenesis.

Cystic Fibrosis↗
PubMed1996

Expression and localization of epidermal growth factor, transforming growth factor-alpha, and localization of their common receptor in fetal human lung development.

Transforming growth factor-alpha (TGF-alpha), epidermal growth factor (EGF), and their common EGF receptor have been shown to be involved in cell proliferation and lung maturation. The aim of the study was to determine the site of production of TGF-alpha and EGF mRNA and the cellular distribution of TGF-alpha/EGF proteins and EGF receptor, in fetal human lung. By using in situ hybridization with 35S-labeled cDNA probes in frozen sections from eight lungs from fetuses ranging from 12 to 33 wk of gestation, TGF-alpha and EGF mRNA transcripts appeared to be confined to the mesenchymal cells and mainly found in the dense connective tissue along the pleura, bronchi, and large vessels, but undetected in bronchial epithelial cells. The streptavidin-biotin immunoperoxidase method, applied to paraffin-embedded specimens from 39 fetuses ranging from 10 to 41 wk, showed that TGF-alpha, EGF, and EGF receptor exhibited a similar cellular distribution during the whole period of gestation. They were detected in the undifferentiated cells of the airway surface epithelium, mesothelial cells, smooth muscle, and a few mesenchymal cells, as early as 10 wk. After 12 wk, the immunoreactivity was strong in the ciliated, secretory, and basal cells, and in growing glands along the large airways, but proved lower in the distal airways. After 24 wk, the immunoreactivity remained in the airway epithelium, but was mainly localized in the apical domain of ciliated cells, in alveolar cells, and in the serous cells of the glands. The presence of TGF-alpha, EGF, and EGF receptor during the whole period of fetal lung development suggests that these factors are not only mitogenic, but can also be involved in epithelial maturation, through paracrine secretion, as most TGF-alpha and EGF mRNA transcripts are expressed in mesenchymal cells.

Antibody Specificity↗
PubMed1995

Determination of reliable histological features associated with early triploidy using DNA image cytometry.

In order to determine reliable histological features characterizing triploidy, the following features were examined and graded by three pathologists on 46 early abortion specimens: hydropic swelling of the villi, cisterns, villous scalloping, trophoblastic hyperplasia with syncytial vacuolization, single cytotrophoblastic cells in villous stroma, trophoblastic inclusions, microcalcifications and fibrosis. At the same time, the DNA content of the 46 specimens was quantified cytophotometrically using the CAS 200 image analyzer, in order to confirm or not the diagnosis of triploidy. Triploidy was confirmed in 45.7%, and in the triploid group, the grading of three features differed significantly from the non triploid group i.e. cisterns (p < 0.001), trophoblastic hyperplasia (p < 0.05) and trophoblastic inclusions (p < 0.05). Using these three features we were able to give a triploid score per slide which represents the sum of the grades of each of these three features. The minimum score obtained was 0, the maximum was 6. The average of these scores in the triploid group was 3.095, and 1.45 in the non triploid group (p < 0.001). This scoring method on the three significant features (cisterns, trophoblastic hyperplasia and trophoblastic inclusions) appears to be useful to classify an abortion specimen as triploid or not, and to select the specimens for which a DNA quantification may be necessary.

Abortion, Spontaneous↗
PubMed1994

Immunohistochemical localization of cystic fibrosis transmembrane conductance regulator in human fetal airway and digestive mucosa.

The cellular distribution of the cystic fibrosis transmembrane conductance regulator (CFTR) in human fetal digestive and respiratory mucosa has been studied by immunohistochemistry. The streptavidin-biotin immunoperoxidase method was applied to paraffin-embedded specimens collected from normal fetuses ranging from 7 to 39 wk of gestation. By the 7th wk, CFTR protein was strongly detected in the yolk sack; in contrast, the staining was weak in the undifferentiated epithelium of the intestine and the airways. At 12 wk, the intestine showed strongly and diffusely stained enterocytes and a basal cytoplasmic reactivity in the first secretory cells. During development, only slight changes could be detected in the digestive epithelial distribution of CFTR. In the airways, the CFTR distribution followed the cephalocaudal maturation. In the tracheal ciliated cells, the CFTR protein was diffusely detected in the cytoplasm as early as 7 wk. After 24-25 wk, CFTR was localized at the apical domain of the ciliated cells and was also present in the collecting ducts and in the glands of the airways, predominantly in the periphery of the acini. Our data suggest that the CFTR is present as early as 7 wk during organogenesis and probably plays an important role during fetal life. There is an evolution in the CFTR distribution during airway development, whereas, in the intestine, CFTR is highly expressed through the epithelium as early as 12 wk and keeps the same distribution until birth.

Antibodies, Monoclonal↗
PubMed1994

[DNA quantification and triploidy phenotype in the second and third trimesters of pregnancy].

Triploidy is often associated with early abortions, but may evolve during the second trimester taking a peculiar phenotype. The conditions of diagnosis or abortion do not always let the possibility of karyotyping. Thus, DNA quantification takes all its value. Twenty-three fetuses and placentas, ranging from 14 to 30 weeks of gestation with a phenotype of triploidy were analysed. Twelve cases were proved by karyotype. The DNA index studied in 6 of these was near 1.5, which confirmed the validity of the technique. Out of 11 phenotypes without karyotyping, DNA analysis identified 4 triploidies and a possible tetraploidy. So, a series of 16 cases could be collected, including 10 partial hydatidiform moles and 6 hypotrophic or normal fetuses and placentas.

Adolescent↗
PubMed1994

[Quantification of DNA using image analysis on paraffin sections].

With the new softwares that are available, it is now possible to measure the cellular DNA content on Feulgen stained paraffin sections, without enzymatic dissociation of the samples. The main advantage of this technique is to preserve the cellular histological context and to select the right cells that have to be analyzed. The application is of course to obtain information about cancer prognosis, but it can also be very useful in non tumoral pathology. The DNA measurement on paraffin sections can be applied to the diagnosis of triploidy or tetraploïdy in spontaneous abortions without any karyotype.

DNA↗
PubMed1993

Ultrasound of the gastroesophageal junction.

In 560 endoscopy examinations performed on infants with severe vomiting, no esophagitis was found without endoscopic herniation of the gastroesophageal junction. The length of the abdominal esophagus therefore appears fundamental in reflux studies. Sonography is one of few techniques able to define the abdominal esophagus in vivo, both in terms of its anatomy and as a functional structure. Accurate assessment of the sonographic canal requires careful measurement under strictly defined clinical conditions. Using such criteria, ultrasound has a better sensitivity than barium studies in detecting small herniations. In addition to the important length measurements of the abdominal esophagus, other morphological and functional data can also be acquired by ultrasound.

Child↗