Renal medullary interstitial infusion of NG-nitro-L-arginine (120 micrograms/hr, n = 7) decreased papillary blood flow to 71 +/- 5% of control without altering outer cortical flow. Before NG-nitro-L-arginine infusion, interstitial acetylcholine administration (200 micrograms/hr) increased cortical and papillary blood flow to 134 +/- 6% and 113 +/- 2% of control, respectively. After NG-nitro-L-a...

The renal medullary countercurrent system differentiates into its final segmental nephron function and geometry during perinatal development. The influence of these changes on the medullary longitudinal osmotic gradient cannot be evaluated by experimental studies. Therefore, a computation analysis using a differential equation model of the renal countercurrent system was applied to quantitate t...

The raphe magnus is part of an interrelated region of medullary raphe and ventromedial reticular nuclei that project to all areas of the spinal gray. Activation of raphe and reticular neurons evokes modulatory effects in sensory, autonomic, and motor spinal processes. Two physiological types of nonserotonergic cells are observed in the medullary raphe and are thought to modulate spinal pain pro...

BACKGROUND: Medullary thyroid cancer, a tumor of the parafollicular C cells, accounts for approximately 10% of all thyroid malignancies. An estimated 75% of cases are sporadic, and the remaining 25% are familial. METHODS: The author reviews the clinical features and diagnostic tests for this entity, as well as the surgical treatment of recurrent or persistent medullary carcinoma. RESULTS: Spora...

The effect of acutely increasing renal perfusion pressure or extracellular fluid volume on renal medullary and cortical blood flow was examined in the low-renin deoxycorticosterone acetate (DOCA)-salt hypertension model in mice. A 50-mg DOCA tablet was implanted, and 1% saline was given as drinking water for 3 wk. Medullary and cortical blood flow were determined with laser-Doppler flowmetry, a...

A medullary thyroid carcinoma is a malignant tumor derived from the C-cells of the thyroid. Despite their distinct embryological origin, medullary thyroid carcinomas are exceptionally accompanied by a tumor derived from the follicular cells; this is defined as mixed medullary and follicular cell carcinoma. There have been controversies regarding the origin of this rare mixed thyroid carcinoma q...

Medullary thyroid carcinoma is a neuroendocrine tumour originating from parafollicular C cells accounting for 5-10% of thyroid cancers. Increased understanding of disease-specific molecular targets of therapy has led to the regulatory approval of two drugs (vandetanib and cabozantinib) for the treatment of medullary thyroid carcinoma. These drugs increase progression-free survival; however, the...

Cabozantinib, a tyrosine kinase inhibitor, was approved by the US Food and Drug Administration in November 2012, for the treatment of metastatic medullary thyroid carcinoma. Although side effects typically include stomatitis, palmar-plantar erythrodysesthesia syndrome, hypertension and diarrhea, most patients are able to tolerate the recommended dose of 140 mg daily. Surgical resection is the p...

This study was prompted by three problems: 1) the role of vasopressin in the countercurrent mechanism for concentrating urine; 2) the effect of dehydration on this mechanism; and 3) the behavior of this mechanism in the absence of vasopressin when the body fluid volumes are contracted rather than expanded. Although it is generally accepted that counter-current systems in the renal medulla effec...

INTRODUCTION Medullary thyroid carcinoma may occur in a sporadic (s-medullary thyroid carcinoma, 75%) or in a multiple endocrine neoplasia type 2 form (MEN2, 25%). These clinical forms differ in many ways, as s-medullary thyroid carcinoma cases are RET-negative in the germline and are typically diagnosed later than medullary thyroid carcinoma in MEN2 patients. In this study, a set of cases with...