Cancer et Hérédité

Sans résumé     

Radiopharmaceutiques et réglementations

The radiopharmaceuticals are products that combine two very stringent regulatory requirements from two different authorities: as medicine from a pharmaceutical point of view (Afssaps) and as radioactive source with specific authorization (ASN). This article discusses the different regulatory constraints imposed by these authorities but suggests also that legislation is supposed to be modified in the coming years in collaboration with nuclear physicians and their Society (SFMN).     

La réaction acrosomique

The acrosome reacting capacity of spermatozoa is essential for the fertilization of the oocyte. Several methods are available for the evaluation of the acrosomal status; each method detects a step of the reaction which is a continuous process. Due to the diversity and the relative specificity of each technique, it is difficult to compare results in absolute values. The reaction is Ca++ dependent. The use of Ca++ ionophores is valuable for a dynamic study which gives a better appreciation of the capacity of spermatozoa to react to a specific stimulus. Many authors have attempted to correlate the acrosomal status to the fertilizing ability of spermatozoa. The results show a reduced induction of AR in hypofertile sperm. More studies with standard materials and methods are needed in order to confirm the diagnostic value of this test.     

Hérédité et épigénétique: un rôle inattendu pour l’ARN

Although Mendel’s first laws explain the transmission of most characteristics, there has recently been a renewed interest in the notion that DNA is not the sole determinant of our inherited phenotype. Human epidemiology studies and animal and plant genetic studies have provided evidence that epigenetic information (“epigenetic” describes an inherited effect on chromosome or gene function that is not accompanied by any alteration of the nucleotide sequence) can be inherited from parents to offspring. Most of the mechanisms involved in epigenetic “memory” are paramutation events, which are heritable epigenetic changes in the phenotype of a “paramutable” allele. Initially demonstrated in plants, paramutation is defined as an interaction between two alleles of a single locus that results in heritable changes of one allele that is induced by the other. The authors describe an unexpected example of paramutation in the mouse revealed by a recent analysis of an epigenetic variation modulating expression of theKit locus. The progeny of hétérozygote intercrosses (carrying one mutant and one wild-type allele) showed persistence of the white patches (characteristic of hétérozygotes) in the homozygous Kit^+/+ progeny. The DNA sequences of the two wild-type alleles were structurally normal, revealing an epigenetic modification. Further investigations showed that RNA and microRNA, released by sperm, mediate this epigenetic inheritance. The molecular mechanisms involved in this unexpected mode of inheritance and the role of RNA molecules in the spermatozoon head as possible vectors for the hereditary transfer of such modifications — implying that paternal inheritance is not limited to just one haploid copy of the genome — are still a matter of debate. Paramutations may be considered to be one possibility of epigenetic modification in the case of familial disease predispositions not fully explained by Mendelian analysis.     

Hypoglycémie spontanée et insuffisance rénale chronique.

Although glucose intolerance occurs as a consequence of chronic renal failure, improvement of a diabetic state by deterioration of renal function is a well known phenomenon. Recently occasional cases of spontaneous hypoglycemia in patients with chronic renal failure have been reported; two such cases and the results of metabolic studies are described in this paper. Pituitary, thyroid and adrenal function appeared to be normal. The results of an oral glucose tolerance test were normal; an appropriate insulin response was demonstrated in one patient, and a slightly elevated basal insulin value with a delayed insulin response to oral administration of glucose was demonstrated in the other. An insulin tolerance test did not support the hypothesis of increased insulin sensitivity as a factor, and the growth hormone response to hypoglycemia was normal. An intravenous glucagon test caused a subnormal increase in plasma glucose concentration, and the intravenous administration of tolbutamide produced hypoglycemia without an increase insulin sensitivity as a factor, and the growth hormone response to hypoglycemia was normal. An intravenous glucagon test caused a subnormal increase in plasma glucose concnetration, and the intravenous administration of tolbutamide produced hypoglycemia without an increase in insulin values. The plasma alanine concentration was low and the proinsulin/insulin ratio was increased. The origin of this hypoglycemia is not clear but is probably multifactorial. However, low hepatic glycogen stores and inadequate gluconeogenesis due to substrate deficiency seem to be involved.     

Comment je raisonne devant une masse rétropéritonéale

The retroperitoneal masses are various and heterogeneous and include tumors from different organs (kidneys), the primary retroperitoneal tumors and metastasis. The primary retroperitoneal tumors are rare, frequently malignant with a delayed diagnosis. More than half of them are sarcoma. Rarity and heterogeneity of retroperitoneal tumors explain the difficulties of diagnostic. The goal of this article is to review the imaging characteristics of CT scan and RMN of retroperitoneal mass and to clarify the diagnosis. The management of sarcoma requires an expert multidisciplinary team (pathologist, radiologist, surgeon, oncologist) and pathology analysis by retroperitoneal transcutaneous biopsy.     

Kyste du tractus thyréoglosse dégénéré révélant un microcarcinome papillaire multifocal de la thyroïde

The malignant degeneration of thyroglossal duct cyst (TDC) is a very rare phenomenon. It occurs 1% of operated cysts where papillary carcinoma represents the most frequent pathological type. The authors report a clinical observation of a papillary carcinoma of thyroid occurring in a thyroglossal duct cyst concomitant to a multifocal micropapillary thyroid discovered in a 21-year-old woman. A total thyroidectomy was performed. A complementary treatment by radioactive iodine 131 (3,7 GBq) was undertaken. Two years later, the patient is doing well and does not present any sign of recurrence. In the light of this observation, the authors propose to report the diagnosis and therapeutic aspects of degenerated thyroglossal duct cyst.     

L'histogenèse régénératrice chez les phoronidiens

Summary The regeneration (organogenesis was studied by Emig, 1972 a, b) of Phoronida can be divided into three phases: the first one, cicatrisation, is characterized by a provisional mesodermal scar-tissue, later the old epidermis cover this scar-tissue. The regenerating blastema, second phase, takes place by cellular dedifferentiation processes; each germ layer (ectoderm, mesoderm, endoderm) regenerates itself from its own elements. One exception only seems to be oesophagel regeneration by metaplasia of the prestomacal cells during the asexual reproduction. The differentiation of the amputated structures (third phase) appears submitted to the inductive influence of the mesoderm and to the trophic action of the nervous system (especially the epithelial plexus). The polarity in regeneration sets a problem in Phoronida.

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Ce travail a été effectué dans le cadre du contrat L. A. n 41 au C. N. R. S.     

Prostatectomie radicale rétropubienne avec préservation nerveuse. Technique et résultats à propos de 200 cas

Objectives

Nerve-sparing radical retropublic prostatectomy carries a risk of leaving positive posterolateral margins with controversial potency recovery rates. We analyses the potency recovery rate and the incidence of positive surgical margins observed with the nerve-sparing procedure in 200 cases.

Methods

Between 1990 and 2000, 605 patients underwent radical retropubic prostatectomy; 200 consecutive potent patients were selected for nerve-sparing: bilateral (87%), unilateral (13%). Mean age was 61.7, mean PSA was 10.48, clinical stage: T1 (41%) T2 (59%), Gleason score: 2 to 6 (81%) 7 to 8 (19%). Specimens were step-sectioned for histological examination, according to the Stanford protocol. Erectile function was evaluated before surgery and postoperatively every 3 months for 2 years. Only patients who achieved unassisted intercourse were considered to be potent.

Results

Positive surgical margins were found in 35 (17%) patients and identified at the nerve-sparing site in 8 (4%) patients. Overall, 157 patients were followed for two years and recovery of potency was observed in 70% of them. On multivariate analysis, the most significant factors affecting postoperative potency were preoperative erectile function and extent of nerve sparing, bilateral versus unilateral; age was not significant.

Conclusions

Nerve-sparing techniques in radical retropubic prostatectomy carry a very low incidence of positive posterolateral margins and yield favorable results in terms of potency recovery.     

Familles moléculaires et réactions croisées en allergie

Le risque pour une personne de développer des manifestations allergiques est plus grand si elle a des antécédents familiaux d’allergie: on parle de terrain atopique.     

Le diagnostic et le suivi thérapeutique des tumeurs cérébrales intra-parenchymateuses par l’imagerie par résonance magnétique multimodale

The multimodal magnetic resonance imaging (MMRI) has an important role in cancer care. This non-invasive and non-ionizing technique provides vital information for the diagnosis and answers to various questions of clinicians before, during and after treatment. The MMRI can specify the localization expanding process; it allows establishing the differential diagnosis of a brain tumor and a circumscribed lesion of another type, to approach the diagnosis of the tumor lesion nature as well as establishing the histological grade of glial tumor in view of lesion monitoring after treatment. The multimodal magnetic resonance imaging has a major contribution to the management progress of the brain tumors. Thus, this paper reviews the value of these MRI modalities in the diagnosis, management and therapy of brain tumors.