Pratique anesthésique pour adénomectomies hypophysaires par voie endonasale à Abidjan, Côte d'Ivoire / Anesthesia for endonasal pituitary adenomectomies in Abidjan, Ivory Coast

L'objectif de l'étude est d'évaluer la pratique anesthésique au cours des adénomectomies hypophysaires par voie endo nasale à Abidjan. Méthode : Il s'agissait d'une étude rétrospective à visée analytique et descriptive, menée entre le 01 janvier 2010 et le 31 décembre 2020 et portant sur les patients admis au bloc opératoire pour une adénomectomie hypophysaire. Les caractéristiques sociodémographiques, cliniques, anesthésiques, évolutives et pronostiques ont été étudiées. Résultats : Nous avons recensé 102 patients. L'âge moyen était de 44,72±12,14 ans. Le sex ratio était de 1. Le délai de diagnostic était d'un an pour 46% (n = 47) des patients. L'hypertension artérielle était l'antécédent le plus retrouvé. Les principaux motifs de consultation étaient les céphalées et les troubles de l'acuité visuelle. Le syndrome d'hypertension intracrânien a été observé chez 67,6% (n= 69) des patients. Tous les patients ont bénéficié d'une consultation pré anesthésique. Cinquante-huit pourcent (n=59) des patients ont été classés ASA I selon la société américaine d'anesthésie. L'anesthésie générale était le seul schéma anesthésique. La durée de l'anesthésie était de plus de trois heures chez 57% (n=58) des patients et le réveil sur table a concerné 88,2% (n=90) des patients. La mortalité était de 3,9%. La durée de l'anesthésie supérieure à 6 heures (p= 0,0012 ; OR= 55,8 [4,88-637,33]) et la perte sanguine supérieure à 1000 ml (p = 0,0228 ; OR=18,6 2,152- 160,747]) ont constitué des facteurs de mauvais pronostic (p<0,05). Conclusion: La réduction de la létalité au cours de l'anesthésie pour adénomes hypophysaires passe par la lutte contre les facteurs de mauvais pronostics

Microdissection and cloning of DNA from landmark loops of amphibian lampbrush chromosomes.

Microdissection of the "globular" and "granular" landmark loops of Pleurodeles lampbrush chromosomes and subsequent cloning of their DNA yielded several recombinant clones. The 6.6-kb insert of one of them was subcloned and the 600 bp of one subclone was characterized by Southern and slot hybridizations as well as by sequencing. This sequence, designated p130B, was shown to belong to a class of moderately repetitive DNA. RNA expression of this sequence was investigated by in situ hybridization of p130B to the nascent transcripts of lateral loops. Results showed that: (1) the same transcripts were not always found in matrices of landmarks exhibiting the same morphological features; (2) the same transcripts were expressed in loops of different morphological types. Based on these results we suggest that even if there is a morphological similarity of landmark loops, this does not reflect total similarity of their transcripts.

Effects of cold shock treatment on lampbrush chromosomes of amphibian oocytes.

When females of the newt Pleurodeles waltl, normally raised in our laboratory at 20 degrees C, were placed in 8 degrees C water for several days, striking modifications occurred in the structure of oocyte lampbrush chromosomes: numerous normal-type lateral loops were partially reduced in size and number, while hyperdeveloped loops of a new morphological type occurred at constant, reproducible loci. However, induction of these cold loops apparently was not accompanied by preferential RNA synthesis at their levels. Cold loops resulted from the decompaction of specific landmarks, the granular loops. Autoradiography revealed a significant drop in lampbrush chromosome transcriptional activity at 8 degrees C. Both structural and transcriptional modifications were fully reversible when oocytes were returned to normal temperature. These modifications are discussed in relation to processes which could determine the morphological appearance of landmark loops.

Chromosomes of amphibian oocytes as a model for gene expression: significance of lampbrush loops.

Amphibian lampbrush chromosome loops exhibit morphological variability in their RNP matrix. The biological significance of such variability remains unknown. In order to approach this problem, the structural organization of each RNP matrix type was analyzed in relation to transcriptional and post-transcriptional processes. First, autoradiographic and transcription inhibition studies in conjunction with macromolecular spread analysis revealed a particular transcription pattern in the most typical loops, i.e. the globular loops. This pattern was characterized by asynchronous variations in RNA synthesis in the different transcription units present in a given loop. Second, morphological and experimental studies provided evidence that the typical morphologies of different RNP matrices were interconvertible and that the differences between the different RNP matrices resulted from various degrees of tightness in packaging of transcription products. In particular, analysis of thermic-shock-induced changes in the structure of lampbrush chromosomes enabled us to visualize the progressive disorganization of dense RNP matrices into globular, granular and normal matrices. Furthermore, these studies suggested that changes in post-transcriptional processes might play a determining role in the specific morphology of the loops. In particular, the kinetics of each of these different processes, related to one another and/or proteins specific to one or another of these processes, might determine the morphological appearance of the loops. The immunological approach revealed that specific nuclear proteins might therefore interfere with each of these processes. Third, the problem of a possible relationship between the specific morphologies of lateral loops and the expression of particular DNA sequences was approached at the molecular level.

Effects of cold shock treatment on amphibian oocytes: alteration of heterogenous nuclear RNP morphology.

In cold-stressed oocytes of Pleurodeles waltl, lampbrush chromosome lateral loops exhibited important structural modifications which were visualized under light microscopy. Electron microscopy study revealed that the RNP particles associated with growing transcripts in the matrix of these loops were 15 nm at 8 degrees C compared to 30 nm at normal temperature (20 degrees C); hnRNP isolated from cold-stressed oocytes sedimented at 15 S in sucrose, while those from control oocytes sedimented at 30 S, as expected. However, under both normal and cold stress conditions, hnRNP possessed a buoyant density of 1.38 g/cm3 in CsCl, indicating that their typical RNA/protein ratio was maintained at 8 degrees C. Our results demonstrate that cold stress affects the structure of hnRNP in amphibian oocytes.

Cold-induced changes in amphibian oocytes.

Female Pleurodeles waltl newts (Amphibia, urodele), usually raised at 20 degrees C, were submitted to low temperatures; oocytes responded to this cold stress by drastic changes both in lampbrush chromosome structure and in protein pattern. Preexisting lateral loops of lampbrush chromosomes were reduced in size and number, while cold-induced loops which were tremendously developed, occurred on defined bivalents of the oocyte at constant, reproducible sites. A comparison of protein patterns in control and stressed oocytes showed two main differences: in stressed oocytes, overall protein synthesis was reduced, except for a set of polypeptides, the "cold-stress proteins"; second, there was a striking inversion of the relative amount of beta- and gamma-actin found in the oocyte nucleus before and after cold stress. Whereas beta-actin was the predominant form in control oocytes, gamma-actin became the major form in stressed oocytes.

Structure of landmark loop ribonucleoprotein matrices in Pleurodeles waltlii lampbrush chromosomes visualized by scanning electron microscopy.

Landmark loop ribonucleoprotein (RNP) matrices of Pleurodeles waltlii lampbrush chromosomes were systematically examined by scanning electron microscopy (SEM). The results, which corroborated similar studies by electron microscopy (EM), showed that RNP transcripts in normal loops, and RNP matrices in granular, globular and dense loops, are composed of one basic structure: an RNP particle with a diameter of 30 nm. SEM observations also clarified the spatial arrangement of this particle in the RNP matrices of all the loop types examined. The specific morphology of normal, granular, globular and dense loop RNP matrices depended on the degree of compaction of the transcription products; this compaction resulted both from the packaging of RNP transcripts and the progressive coiling of the loop axis.

Size uniformity of ribonucleoprotein matrix particles in loops of Pleurodeles waltlii lampbrush chromosomes visualized by electron microscopy.

The different kinds of loops of lampbrush chromosomes were identified in phase contrast, then analysed by electron microscopy on thin sections. Examination at high magnification showed that the basic structure of the ribonucleoprotein (RNP) matrix of all kinds of loops is a 30 nm RNP particle. Furthermore, this study suggests that the morphological differences between the loops are due to the extent of aggregation of these particles.

Evidence for a particular mode of transcription in globular loops of lampbrush chromosomes of the newt Pleurodeles waltlii.

In amphibian lampbrush chromosomes, many loops have a specific morphology; this is the case for globular loops in the newt Pleurodeles. We have previously shown that the specific morphology of these loops is linked to an extreme compactness of the transcription products which make up their matrix. We investigated RNA synthesis in this type of loop by carrying out autoradiographic and transcription inhibition studies. We also analysed the organization of transcriptional complexes in these loops in the electron microscope using spread preparations. These studies revealed the presence of several transcription units in the same loop and asynchronous variations in RNA synthesis in these transcription units. We propose and discuss several hypotheses in order to explain this asynchronous RNA synthesis. We also discuss these results in the context of loop morphology and transcription mode.