Heinz Geerlings

Compartment-oriented microdissection of regional lymph nodes in medullary thyroid carcinoma

Lymph node metastases have been proven to be the main prognostic factor in medullary thyroid carcinoma (MTC). This retrospective study was undertaken to evaluate the efficiency of two surgical techniques of regional lymph node dissection with regard to the normalization of pentagastrin-stimulated serum calcitonin level and patient survival: selective lymphadenectomy, i.e., the excision of macroscopically or microscopically involved lymph nodes, versus a systematic lymphadenectomy performed by the new technique of a compartment-oriented microdissection. From 1970 to 1990, 82 patients with sporadic (n=57) and hereditary (n=25) MTC underwent a total of 142 operations including 63 selective lymphadenectomies and, since 1986, 35 systematic lymphadenectomies. The study revealed that in node-positive MTC the rate of interventions with a postoperative normalization of pentagastrin-stimulated serum calcitonin was higher after systematic lymphadenectomy (29.2%) than after selective lymphadenectomy (8.5%) (P<0.01). The rate of patients undergoing repeat surgery due to a recurrence of MTC was 48% after selective lymphadenectomy and 10% after systematic lymphadenectomy. Survival was significantly better for patients after systematic versus selective lymphadenectomy (P<0.005). This study thus emphasizes that systematic lymphadenectomy, using the technique of a compartment-oriented microdissection of cervicomediastinal lymph nodes, represents the preferred surgical treatment as well as the optimum technique in primary as well as secondary node-positive MTC.

Influence of age, strain and season on circadian periodicity of pituitary, gonadal and adrenal hormones in the serum of male laboratory rats.

The influence of age, strain and season on the circadian pattern of serum levels of LH, FSH, prolactin androgens and corticosterone was studied in five groups of male laboratory rats. Significant 24-hour periodicity was observed for serum levels of corticosterone in all five groups, for androgen levels in four, for prolactin levels in three, for LH levels in two and for FSH levels in one group of rats. There were significant influences of age, strain and season on the temporal patterns and/or on 24-hour mean serum hormone levels. The results indicate that some of the disagreements on existence or nonexistence of circadian rhythms and on rhythm patterns in serum hormone levels may be explained by the fact that animals of different ages or strains had been used or that experiments were performed at different times of the year.

Postnatal treatment of rats with adrenergic receptor agonists or antagonists influences differentiation of sexual behavior.

The aim of the study was to investigate the possible role of the adrenergic system in development and differentiation of neural centers controlling sexual behavior in adulthood. For this purpose normal and androgenized female rats were treated with the alpha 1-receptor antagonist prazosin, the alpha 2-receptor agonist clonidine, or the alpha 2-receptor antagonist yohimbine-HCl throughout the first week of life. In adulthood all animals were ovariectomized and, after appropriate hormone-priming, they were tested for the capacity to display female and male sexual behavior patterns. Alteration of adrenergic transmission during the critical postnatal period for sexual differentiation of neural centers resulted in significant changes in the capacity to express female lordosis behavior in adulthood. In nonandrogenized animals clonidine significantly reduced the capacity for lordosis behavior. In androgenized animals clonidine had the opposite effect; it attenuated the inhibitory effect of testosterone propionate (TP) on differentiation of lordosis behavior. Prazosin, which was without effect in nonandrogenized animals, also attenuated the inhibitory effect of TP on differentiation of lordosis behavior. Yohimbine was without effect in androgenized and nonandrogenized animals. There was no influence of any of the adrenergic drugs on differentiation of male sexual behavior. In conclusion, differentiation of lordosis behavior seems to be mediated or modulated via adrenergic transmission. The defeminizing effect of testosterone postnatally on the differentiation of lordosis behavior seems to be expressed via alpha 1-adrenergic transmission, and diminished adrenergic activity during the postnatal period seems to protect the developing brain against this effect of testosterone.