New time-shifted Z-score and Student's test in fMRI

A new approach to compute z-score and Student's test in functional MRI has been developed. This approach tends to involve standard z-score and Student's test computation. This approach is based on the delay of the response compared to the stimulation introduced by many authors. The results obtained prove the methods efficiency; moreover these methods can be easily adapted in a clinical context. This paper presents the new computation and the validation.

[Thyroid dysfunction and pregnancy]

The pregnancy is a state of thyroid hyperstimulation, therefore of changes of thyroid hormone values. Results of thyroid hormone measurement have to be analysed in the context of gestation age. Hyperthyroidism, mostly represented by Graves' disease, requires a multidisciplinary management, owing to possible maternal, foetal and neonatal complications. Treatment with antithyroid drugs, is a compromise between the risk of uncontrolled maternal hyperthyroidism and the risk of iatrogenic foetal hypothyroidism. Evaluation of foetal thyroid function considers the titre of thyrotropin receptor antibodies in the mother's blood, the dose of antithyroid drugs to maintain euthyroidism in the mother, and the signs of foetal hyperthyroidism on ultrasound. Maternal hypothyroidism is associated with foetal and maternal morbidity. Untreated or inappropriately treated, it is associated with poorer performances of offspring in intelligence tests. Thyroid autoimmunity is associated with hypofertility, particularly with spontaneous abortion. Screening for thyroid dysfunction during pregnancy, although not systematic, should have broad indications.

Low oocyte mitochondrial DNA content in ovarian insufficiency

BACKGROUND

Mitochondrial biogenesis and bioenergetics play an important role in oocyte maturation and embryo development. We have investigated the relationship between defective mitochondrial biogenesis and the lack of oocyte maturity observed during IVF procedures with patients suffering from ovarian dystrophy and ovarian insufficiency.

METHODS

We used real-time quantitative PCR to quantify mitochondrial DNA (mtDNA) in 116 oocytes obtained from 47 women undergoing the ICSI procedure. We compared the mtDNA content of oocytes from women with a normal ovarian profile with that of oocytes from women with ovarian dystrophy and ovarian insufficiency.

RESULTS

We found an average of 256,000 +/- 213,000 mitochondrial genomes per cell. The mean mtDNA copy number was not significantly different in ovarian dystrophy compared with controls, but it was significantly lower in oocytes from women with ovarian insufficiency (100,000 +/- 99,000, P < 0.0001).

CONCLUSIONS

Our results suggest that low mtDNA content is associated with the impaired oocyte quality observed in ovarian insufficiency.

Abnormal stimulation of the thyrotrophin receptor during gestation

Pregnancy induces physiological alterations in thyroid function which may make difficult the interpretation of results of thyroid hormone measurement. A state of hyperstimulation of the thyroid gland is common in early pregnancy. In a few cases, thyroid hormone values will deviate from the normal range, which corresponds to the gestational transient thyrotoxicosis. This syndrome is closely associated with hyperemesis gravidarum. The relationship between the two syndromes, demonstrated by epidemiological studies, has been illustrated by an exceptional case of familial recurrent gestational thyrotoxicosis presenting as hyperemesis gravidarum due to hypersensitivity of the thyrotrophin receptor to hCG. However, the exact mechanisms of hyperemesis gravidarum have not yet been identified. Gestational transient thyrotoxicosis has to be distinguished from Graves' disease, because the latter is associated with potential maternal and fetal complications when thyrotoxicosis is not controlled, whereas the former has usually a favourable outcome. The existence of other cases of thyroid hypersensitivity or hCG endowed with abnormal thyrotrophic activity is suspected. They may be identified only by assessment of the thyroid function in cases of hyperemesis gravidarum. The identification of these cases would be helpful to understand the mechanisms of specificity of glycoprotein hormone receptors.

Increased sperm mitochondrial DNA content in male infertility

BACKGROUND

There is increasing evidence that mitochondrial DNA (mtDNA) anomalies in sperm may lead to infertility. Point mutations, deletions and the presence of a specific mtDNA haplogroup have been associated with poor sperm quality, but little attention has been paid to the role of mtDNA content.

METHODS

Using density gradient separation and swim-up methods, we selected motile sperm from 32 normal and 35 abnormal sperm samples. The mtDNA/beta-globin gene ratio was determined by real-time quantitative PCR.

RESULTS

The average mtDNA/beta-globin ratio of sperm collected from 100% density layers was 1.4 for normal sperm, 6.1 for sperm samples presenting at least one abnormal criterion [among the three criteria established by World Health Organization (1999), i.e. sperm count, motility and morphology], and 9.1 for sperm samples presenting two or more of these abnormal criteria. These differences are very highly significant (P < 0.0001). The mtDNA numbers were also much greater in sperm collected from the 40% density gradient layers (mean: 17.1, P < 0.001), known to contain the most abnormal sperm of the sperm samples, than in those collected from the 100% layers known to contain sperm with the best fertilizing ability.

CONCLUSION

Our results showed significant mtDNA amplification in sperm collected from abnormal sperm samples.

[Induce or not induce labor in gestational diabetes]

The most serious hazard of gestational diabetes is shoulder dystocia, which sometimes is complicated by Erb's palsy and maternal lacerations. This risk is linked to fetal weight, and is more frequent in cases of diabetes. So, a caesarean section performed when macrosomia is present is required and an induction of labor before severe macrosomia is proposed. Unfortunately, estimation of fetal weight is imprecise in spite of formulas from fetal parameters. Abdomen circumference (AC) alone is as effective as complex formulas. So, it is proposed to perform an elective section when AC is equal or above 38 cm, and to induce labor, after 38 weeks of gestation, for limiting the risk of macrosomia when AC is between 35 and 38 cm. Induction is also proposed when pregnancy is complicated by hypertension or when fetal heart septal hypertrophy occurs. The management of gestational diabetes means a strict control of glycemia, which can reduce macrosomia and the need for cesarean section or induction of labor.

Volume delineation by fusion of fuzzy sets obtained from multiplanar tomographic images

Techniques of three-dimensional (3-D) volume delineation from tomographic medical imaging are usually based on 2-D contour definition. For a given structure, several different contours can be obtained depending on the segmentation method used or the user's choice. The goal of this work is to develop a new method that reduces the inaccuracies generally observed. A minimum volume that is certain to be included in the volume concerned (membership degree mu = 1), and a maximum volume outside which no part of the volume is expected to be found (membership degree mu = 0), are defined semi-automatically. The intermediate fuzziness region (0 < mu < 1) is processed using the theory of possibility. The resulting fuzzy volume is obtained after data fusion from multiplanar slices. The influence of the contrast-to-noise ratio was tested on simulated images. The influence of slice thickness as well as the accuracy of the method were studied on phantoms. The absolute volume error was less than 2% for phantom volumes of 2-8 cm3, whereas the values obtained with conventional methods were much larger than the actual volumes. Clinical experiments were conducted, and the fuzzy logic method gave a volume lower than that obtained with the conventional method. Our fuzzy logic method allows volumes to be determined with better accuracy and reproducibility.

Evidence for the presence of tropomyosin in the cytoskeletons of ADP- and thrombin-stimulated blood platelets

Stimulation of porcine platelets with ADP or thrombin and subsequent analyses of their cytoskeletons by SDS-polyacrylamide gel electrophoresis have shown the presence of a 30.5-kDa polypeptide in the cytoskeletons of activated as well as aggregated platelets. This polypeptide comigrates with pure porcine platelet tropomyosin in SDS gels, their mobilities being similarly and markedly decreased in the presence of 6 M urea. One-dimensional peptide mapping after limited proteolysis by Staphylococcus aureus protease gives the same pattern for pure tropomyosin and the 30.5-kDa polypeptide. This latter may thus be identified as the porcine platelet tropomyosin subunit, the role of which may not be solely structural.

Combined effects of NaCl, NaOH, and biocides (monolaurin or lauric acid) on inactivation of Listeria monocytogenes and Pseudomonas spp

This study highlighted combinations of chemical stresses that could decrease or eliminate Listeria monocytogenes and Pseudomonas spp. surviving in food processing plants. Strains of L. monocytogenes, Pseudomonas fragi, and Pseudomonas fluorescens isolated from processing environments (meat and milk) were grown at 20 degrees C up to the early stationary phase. The strains were then subjected to 30 min of physicochemical treatments. These treatments included individual or combined acid (acetic acid), alkaline (NaOH), osmotic (NaCl), and biocides (fatty acids) challenges. Survival of the strains was studied after individual or combined acid (acetic acid), alkaline (NaOH), osmotic (NaCl), and biocides (monolaurin, lauric acid) challenges. Individual pH shocks had lower efficiencies than those used in combinations with other parameters. The treatment pH 5.4 followed by pH 10.5 had a low efficiency against L. monocytogenes. The opposite combination, pH 10.5 followed by pH 5.4, led to a 3-log reduction of the L. monocytogenes population. Pseudomonas spp. strains were much more sensitive than L. monocytogenes, and population reductions of 5 and 8 log (total destruction), respectively, were observed after the same treatments. As for L. monocytogenes, the combination pH 10.5 followed by pH 5.4 is more deleterious than the opposite. Whatever the bacterial species, the most efficient treatments were combinations of alkaline, osmotic, and biocide shocks. For instance, the combination pH 10.5 and 10% NaCl plus biocides showed reductions of 5 to 8 log for both bacteria. The origins of the observed lethal effects are discussed.

3D reconstruction of the encapsulating contour of arteriovenous malformations for radiosurgery using digital subtraction angiography

PURPOSE

Treatment planning for radiosurgery depends on the precise definition of radiation target volumes. For vascular pathologies such as arteriovenous malformations (AVM), the most usual technique remains standard X-ray projection imaging, most often carried out under stereotactic conditions. To further benefit from the advantages of two-dimensional digital subtraction angiography (DSA), the authors have developed a method for determining the three-dimensional shape of arteriovenous malformations from two views.

METHODS AND MATERIALS

After correction of image intensifier distortion and calibration of both views, the 3D shape of the AVM was determined from two DSA projections using epipolarity geometry. The AVM-encapsulating contour was modeled by triangulation of a stack of almost parallel ellipses. The method was technically validated using artificial targets in a skull phantom. Clinical validation was carried out on 10 patients who were examined using both conventional angiography under stereotactic conditions (SX-ray) and DSA.

RESULTS

There was excellent agreement between the artificial target volumes measured with SX-ray and with DSA. The correspondence between AVM volumes found for patients was not as good as with the phantom.

CONCLUSIONS

The different image characteristics of the two modalities lead to some differences in AVM estimations. However, the results were sufficiently satisfactory to justify routine use of this AVM modeling technique for radiosurgery planning.

Accurate localization of needle entry point in interventional MRI

In interventional magnetic resonance imaging (MRI), the systems designed to help the surgeon during biopsy must provide accurate knowledge of the positions of the target and also the entry point of the needle on the skin of the patient. In some cases, this needle entry point can be outside the B(0) homogeneity area, where the distortions may be larger than a few millimeters. In that case, major correction for geometric deformation must be performed. Moreover, the use of markers to highlight the needle entry point is inaccurate. The aim of this study was to establish a three-dimensional coordinate correction according to the position of the entry point of the needle. We also describe a 2-degree of freedom electromechanical device that is used to determine the needle entry point on the patient's skin with a laser spot.

Comparison between exercise whole body thallium imaging and ankle-brachial index in the detection of peripheral arterial disease

BACKGROUND

Exercise whole body thallium imaging and rest/exercise ankle-brachial index can provide evidence of peripheral artery disease at the stage of intermittent claudication. The aim of this study was to compare both methods in the detection of asymptomatic peripheral artery disease.

METHODS

EXPERIMENTAL DESIGN

prospective non-randomised study.

SETTING AND PATIENTS

general community, private practice, ambulatory patients referred in a Nuclear Medicine Department for exercise myocardial scintigraphy. Intermittent claudication was present in 8% of the whole study population. Coronary artery disease and diabetes were respectively present in 70% and 16% of the same population.

MEASURES

rest/exercise ankle-brachial index and exercise whole body thallium imaging were measured in 105 patients (76 men and 29 women, mean age +/- 1 SD= 61 +/- 10 year) who performed a near-maximal or maximal treadmill test. Normal values of regional blood supply and indices of asymmetry at different levels of legs were determined in 14 patients with a very low probability of peripheral artery disease.

RESULTS

The probability of peripheral artery disease was very high in 19 patients (group 1), because of abnormal rest and/or exercise ankle-brachial index, whereas in the 86 remaining patients, the index at rest and exercise was quite normal (group 2).With respect to rest and/or exercise ankle-brachial index, the sensitivity, specificity, positive and predictive negative value of exercise scintigraphy abnormalities were respectively 89%, 62%, 34% and 96%. The false positive scan group differed from the true positive group only by sex and redistribution of thallium 201. The proportion of diabetic patients was the same (15%) in both groups.

CONCLUSIONS

Exercise whole body thallium imaging might contribute without additional cost to the detection, functional evaluation and/or risk stratification of peripheral artery disease in patients who perform exercise myocardial scintigraphy.

Establishment of the paternal methylation imprint of the human H19 and MEST/PEG1 genes during spermatogenesis

Parental-specific epigenetic modifications are imprinted on a subset of genes in the mammalian genome during germ cell maturation. However, the precise timing of their establishment remains to be determined. Methylation of CpG dinucleotides has been shown to be a part of the parental imprint. We have examined how the methylation pattern characteristic of the paternal allele in germ cells are established during human spermatogenesis. Two representative imprinted genes, H19 and MEST/PEG1, were studied. The experiments were performed using the bisulphite sequencing method on microdissected individual cells at different stages of male germ cell differentiation. We show that both genes are unmethylated in fetal spermatogonia, suggesting that all pre-existing methylation imprints are already erased by this stage. The MEST/PEG1 gene remains unmethylated at all subsequent post-pubertal stages of spermatogenesis, including mature spermatozoa. The methylation of H19 typical of the paternal allele first appears in a subset of adult spermatogonia and then is maintained in spermatocytes, spermatids and mature spermatozoa. Our results suggest that the methylation imprint inherited from the parents is first erased in the male germ line at an early fetal stage. The paternal-specific imprint is re-established only later, during spermatogonial differentiation in the adult testis.

Bioassays of gonadotropins

Bioassays constitute a unique approach to determine the functional aspects of gonadotropins. Indeed, these highly complex glycoprotein hormones, including pituitary lutropin (LH) and follitropin (FSH), are heterogeneous in terms of both peptidic and carbohydrate moieties, and, as a consequence, the bioactivity of the different molecular forms often does not match their immunoreactivity. In this article, we review the different types of LH and FSH bioassays. Conventional methods for measuring FSH bioactivity are first described and include the in vivo Steelman and Pohley bioassay, the radioligand receptor assays (RRAs), the in vitro Sertoli cell bioassay, the in vitro granulosa cell bioassay, and the inhibin immunoassay. Recent methods based on cell lines transfected with cloned receptors, particularly the human FSH receptor, are then described. Methods for developing these assays are presented, and the advantages and disadvantages of the different bioassays are discussed.

[Qualitative retrospective study comparing 43 advanced-rotated flaps to 19 island type Venkataswami-Subramanian flaps]

OBJECTIVE

In case of a fingertip trauma, the surgeon'aim is to give the finger a good function, that means a fingertip with good sensibility and trophicity. The purpose of this study was to follow-up three different types of flaps used for fingertip reconstruction, and to analyse their sensibility and functional results.

METHOD

62 fingertip-flaps performed in 60 patients were included in this series. Patients were mainly males (45-60), adults (42-60), middle age (mean age = 40), right-handed (55-60) and home-injured (32-60). The dominant side was injured more often (43-60), by section (27-60) or crush (25-60). Patients were reviewed by the same investigator. Various types of flaps were used: 31 Atasoy flaps, 19 neurovascular island unipedicled flaps and 12 Hueston flaps. Sensory results were evaluated using static and moving two-point discrimination tests, and pain and hot-cold discrimination. Esthetic and functional results were also evaluated.

RESULTS

The tactile sensibility was good or excellent in 63% of flaps and the nail looked good in 70% of flaps. Among all flaps, the Atasoy flap obtained the best results.

DISCUSSION

This study showed the good quality of Atasoy and Hueston flaps in fingertip reconstruction. Neurovascular island flaps gave poor results without taking in account the severity of initial trauma.

3D reconstruction of the cerebral arterial network from stereotactic DSA

The authors present an automatic algorithm for 3D reconstruction of cerebral blood vessels by digital subtracted angiography. The patient is localized by a stereotactic method. The reconstruction algorithm includes two steps: first vessel extraction then 2D matching and reconstruction. Accurate vessel skeletons are generated by a combination of mathematical morphological algorithms and adaptive filters. The 3D reconstruction algorithm is based on the reconstruction of vessels center lines. For that purpose, three different projections of the vascular network are used. Reconstruction is computed segment by segment (a curved line between two nodes). For each segment point, the algorithm defines all epipolar solutions on the other views. These epipolar solutions are sorted and pooled by 2D continuity and 3D proximity criteria resulting in a 3D graph. Optimal 3D segment is defined by a recursive algorithm that looks up the better path in the 3D graph. The algorithms have been implemented on a Compatible-PC computer in C language. More than 95% of static copper phantom was reconstructed in 5 min and with 1 mm 3D accuracy. 70% of arteries (from carotid to the seventh node) of a true patient arterial network were reconstructed is less than 30 min.

Differential protein expression by Pseudomonas fragi submitted to various stresses

We have analyzed the impact of various stressing conditions on the physiological and molecular responses of the main psychrotrophic spoilage bacterium of refrigerated meat and meat products, Pseudomonas fragi. A survival study using conventional plating was first performed to select the stressing agents and parameters. Some of these mimicked cleaning-disinfection processes but with less drastic conditions in order to keep alive enough bacterial cells for the protein expression characterization. Cultures of P. fragi, at the beginning of the stationary phase of growth, were submitted to individual pH (5.4, 10.5), osmotic (8% Na2SO4, pH 7.0), biocide (fatty amine) shocks or combined treatments (8% Na2SO4, pH 10.5; 8% Na2SO4, pH 10.5 + biocide; pH 5.4 + pH 10.5 and pH 10.5 + pH 5.4) and the molecular responses were investigated by comparing autoradiograms of two-dimensional gel electrophoresis (2-DE) patterns of proteins radiolabeled with L-[35S]methionine. The observation of qualitative and relative quantitative variations in protein expression, determined with Melanie II image analysis software (Bio-Rad), revealed the overexpression of a total of 91 proteins for the eight challenges by comparison with the nonshocked controls. Some proteins appeared to be more or less general stress proteins whereas others were specific for one chemical treatment. The appraisal of the type of molecular response according to the type of treatment was analyzed statistically.

Mutations in the gene encoding mevalonate kinase cause hyper-IgD and periodic fever syndrome. International Hyper-IgD Study Group

Hyperimmunoglobulinaemia D and periodic fever syndrome (HIDS; MIM 260920) is a rare, apparently monogenic, autosomal recessive disorder characterized by recurrent episodes of fever accompanied with lymphadenopathy, abdominal distress, joint involvement and skin lesions. All patients have high serum IgD values (>100 U/ml) and HIDS 'attacks' are associated with an intense acute phase reaction whose exact pathophysiology remains obscure. Two other hereditary febrile disorders have been described. Familial Mediterranean fever (MIM 249100) is an autosomal recessive disorder affecting mostly populations from the Mediterranean basin and is caused by mutations in the gene MEFV (refs 5,6). Familial Hibernian fever (MIM 142680), also known as autosomal dominant familial recurrent fever, is caused by missense mutations in the gene encoding type I tumour necrosis factor receptor. Here we perform a genome-wide search to map the HIDS gene. Haplotype analysis placed the gene at 12q24 between D12S330 and D12S79. We identified the gene MVK, encoding mevalonate kinase (MK, ATP:mevalonate 5-phosphotransferase; EC 2.7.1.36), as a candidate gene. We characterized 3 missense mutations, a 92-bp loss stemming from a deletion or from exon skipping, and the absence of expression of one allele. Functional analysis demonstrated diminished MK activity in fibroblasts from HIDS patients. Our data establish MVK as the gene responsible for HIDS.

Effect of osmotic, alkaline, acid or thermal stresses on the growth and inhibition of Listeria monocytogenes

Five strains of Listeria monocytogenes (a, b, c, d and e) isolated from industrial plants have been subjected to different osmotic, alkaline, acid or thermal stresses. The effects of these treatments on lag-phase (L) and growth rate (mu) of cells in mid-log phase have been followed using an automated optical density monitoring system. Increasing the osmotic pressure by the addition of different amounts of NaCl increased the lag phase and decreased the growth rate. The same phenomena were observed after decreasing the pH of the medium to 5.8, 5.6 or 5.4 by addition of acetic, lactic or hydrochloric acids. The inhibitory effect was: acetic acid > lactic acid > hydrochloric acid. The addition of NaOH to attain pH values of 9.5, 10.0, 10.5 or 11.0 in the medium produced a dramatic increase of the lag phase at pH 10.5 and 11. Growth rates were also decreased while the maximal population increased with high pH values. These effects varied according to strains. Strains d and e were the most resistant to acidic and alkaline stresses, and e was the most affected by the addition of NaCl. A cold shock of 30 min at 0 degree C had limited effects on growth parameters. On the other hand, hyperthermal shocks (55 or 63 degrees C, 30 min) led to similar increased lag phases and to significant increases of the maximal population in all five strains.

Genes and premature ovarian failure

Premature ovarian failure (POF) is an heterogeneous syndrome. Among genetic causes, X monosomy as in Turner syndrome or X deletions and translocations are known to be responsible for POF. The genes involved in ovarian function, located on the X chromosome are still unknown. On the other hand, autosomal abnormalities have been identified in POF patients such as mutations of the FSH gene, the LH and FSH receptor genes, chromosome 3q containing the blepharophimosis gene, the ATM gene (Ataxia-telangiectasia gene). Mutations in the AIRE gene (responsible for APECED syndrome) can involve ovarian insufficiency. It is likely that studies on the function of the protein AIRE might improve our knowledge on follicular development. Furthermore, different mouse models of ovarian failure such as mouse lacking connexins or mice lacking GDF9 (growth derived factor 9), might increase our knowledge of ovarian failure. In the future, a better knowledge of the cellular and biochemical components involved in folliculogenesis and apoptosis should elucidate the mechanisms of POF.