The neuroendocrine challenge paradigm in headache research

The neuroendocrine challenge paradigm provides a "window" on central neurotransmitter function in vivo. This strategy is based on the premise that the sensitivity of certain central receptors can be inferred from the magnitude of the hormonal response to specific pharmacologic probes. For example, the serotonin (5HT) receptor agonist m-chlorophenylpiperazine (m-CPP) stimulates the release of cortisol and prolactin and induces migraine-like headaches. We have previously reported that the headache and cortisol responses to m-CPP are highly correlated, which may implicate a disturbance in central serotonergic neurotransmission in the pathogenesis of migraine. As pharmacologic probes with greater specificity for 5HT receptor subtypes become available, we may be able to elucidate these mechanisms with greater precision. The neuroendocrine challenge methodology is also applicable to the study of other neurotransmitter systems and other headache disorders.     

Hepatocellular carcinoma: assessment of resectability by computed tomography and ultrasound

A retrospective review of the CT and ultrasound scans from examinations of 30 patients who had hepatocellular carcinoma (hepatoma) was undertaken with special emphasis placed on evaluation of hepatic distribution of tumor, vascular invasion, and extrahepatic spread. Although both CT and ultrasound detected hepatoma in 29 of 30 patients (96%), CT showed more extensive hepatic parenchymal involvement in eight of the patients. Vascular invasion was seen more frequently with ultrasound than with CT. Invasion into the main portal vein was seen by ultrasound in 11 of 30 patients (37%). Extrahepatic spread of tumor was much more frequently detected by CT and was present in 21 of 30 patients (70%). A reasoned approach to the diagnostic workup of hepatomas that will minimize invasive procedures and unnecessary surgery is presented.