[Timing of gonadectomy in patients with complete androgen insensitivity syndrome]. / Quand proposer une gonadectomie chez les patientes présentant une insensibilité complète aux androgènes ?

Complete androgen insensitivity syndrome is the most frequent cause of disorder of sexual development in 46 XY patients. It is caused by mutations of the AR gene coding for the androgen receptor. Transmission is X-linked and mutations are most of the time inherited. It leads to a complete lack of response to androgen resulting in the presence of female external genitalia in 46 XY patients, normal but undescended testes and lack of female internal genitalia due to the secretion of anti-Müllerian hormone by male gonads. Traditionally, gonadectomy was proposed before puberty to decrease the risk of gonadal malignancy. However, more recent studies underlined the benefits of postponing gonadectomy until after pubertal development. Benefits of deferred gonadectomy are spontaneous pubertal development through peripheral aromatization of testosterone into oestrogens and the chance for the patient to have an active role in the decision-making process. After gonadectomy, hormone replacement therapy is required in order to prevent complications due to hypogonadism such as osteoporosis, cardiovascular diseases and a reduction of life expectancy.

L'insensibilité aux androgènes est l'étiologie principale des troubles du développement sexuel chez des patientes 46 XY. Elle est due à des mutations du gène AR qui code pour le récepteur des androgènes. Le mode de transmission est lié à l'X et les mutations sont le plus souvent héritées. Il en résulte une absence d'action des androgènes sur leurs récepteurs entraînant la présence d'organes génitaux externes féminins chez des patientes 46 XY, de testicules normalement développés en position abdominale ou inguinale et en l'absence d'organes génitaux internes féminins due à la sécrétion d'hormone anti-müllérienne par les gonades masculines. La gonadectomie était auparavant effectuée en période pré-pubertaire en raison du risque suspecté de développement de néoplasie maligne. Des données récentes suggèrent la possibilité de postposer cette intervention après le développement pubertaire. Le risque de transformation maligne pré-pubertaire des gonades est faible, et différer la gonadectomie permet un développement pubertaire naturel grâce à l'aromatisation périphérique de la testostérone en œstradiol. Ce délai permet d'impliquer activement la patiente dans la prise en charge de sa pathologie. Après la gonadectomie, un traitement hormonal substitutif par œstrogènes est indiqué pour prévenir les complications dues à l'hypogonadisme telles que l'ostéoporose, les maladies cardio-vasculaires et la réduction de l'espérance de vie.

Neuron loss and shrinkage in the amygdala in Alzheimer's disease.

Total neuron numbers in the amygdala and in eight of its subnuclei were determined in 9 cases of Alzheimer's disease (AD) and in 6 age-matched controls (AMC). Total neuron numbers were obtained using the fractionator. A neuron loss of 56.3% for the left amygdala and 50.5% for the right amygdala in AD was found, being more severe than previously reported. The subdivisions showed a differential neuron loss ranging from 35.5% in nucleus lateralis of the right amygdala to 70.4% in the nucleus basalis accessorius of the right amygdala. Moreover, a shift in size distribution to smaller neurons could be demonstrated. No left-right hemispheric differences were detected in total neuron numbers in AD and AMC.

Loss of collagen from experimental intestinal anastomoses: early events.

Collagen lysis, which always occurs to some extent in the wound area, is thought to be the underlying cause for breakdown of intestinal anastomoses. Therefore, we have studied the loss of collagen around ileal and colonic anastomoses in New Zealand White rabbits during the first 48 hr after operation. In the ileum, significant lysis of collagen in the anastomotic area, as represented by a decreased level of hydroxyproline, occurs from 12 hr postoperatively onward. Maximal loss of hydroxyproline, as compared to preoperative values, is 27% measured 24 hr after operation. In the colon, significant lysis of collagen occurs after 3 hr. The lowest level of hydroxyproline measured during the experimental period is found 48 hr after operation, where the concentration is decreased by 38%. Changes in ileum are restricted to the anastomotic area, while in the colon the decrease in hydroxyproline extends along the intestinal wall, particularly in a proximal direction. The fact that total protein concentrations do not vary significantly indicates that the lowered hydroxyproline levels are specific. Microscopic examination of the wound area shows that the cellular response during the first 24 hr after wounding is restricted to granulocytes. It is suggested that granulocyte collagenase is mainly responsible for the observed lysis of collagen after intestinal anastomosis.