Undetectable Serum Thyroglobulin in Patients With Differentiated Thyroid Cancer: Antithyroglobulin Antibodies, Assay Limitation, or Other?

Objective: To determine why some patients with differentiated thyroid cancer (DTC) lymph node (LN) metastases do not have detectable serum thyroglobulin (Tg).

Methods: Fine needle aspiration biopsy (FNAB) washout fluid from patients with DTC LN metastases and undetectable serum Tg measurement by immunoassay (Tg-IA) were evaluated for the presence of Tg and anti-Tg antibodies (TgAbs). Spike-recovery experiments in serum were performed to assess the reason for undetectable Tg.

On the origin of grasshopper oviposition behavior: structural homology in pregenital and genital motor systems.

In female grasshoppers, oviposition is a highly specialized behavior involving a rhythm-generating neural circuit, the oviposition central pattern generator, unusual abdominal appendages, and dedicated muscles. This study of Schistocerca americana (Drury) grasshoppers was undertaken to determine whether the simpler pregenital abdominal segments, which do not contain ovipositor appendages, share common features with the genital segment, suggesting a roadmap for the genesis of oviposition behavior. Our study revealed that although 5 of the standard pregenital body wall muscles were missing in the female genital segment, homologous lateral nerves were, indeed, present and served 4 ovipositor muscles.