Mediastinal lymph node involvement in non-small cell lung cancer: evaluation with 99mTc-tetrofosmin SPECT and comparison with CT.

In patients with non-small cell lung cancer (NSCLC), surgical resection offers the best chance of cure. The preoperative assessment of mediastinal lymph node involvement is crucial to selecting those patients for whom surgery is indicated. METHODS: To evaluate the possible clinical role of (99m)Tc-tetrofosmin scintigraphy in the presurgical detection of mediastinal node metastases from NSCLC, we performed a prospective comparative study with CT on 83 patients (48 men, 35 women; age range, 38-81 y) with primary NSCLC (36 adenocarcinomas, 39 epidermoid squamous cell carcinomas, and 8 large cell anaplastic carcinomas). They underwent chest SPECT 20 min after (99m)Tc-tetrofosmin injection (740 MBq intravenously). The metastatic involvement of mediastinal nodes was assessed by histologic examination after mediastinoscopy or thoracotomy. Both chest CT and (99m)Tc-tetrofosmin scintigraphy were performed within 2 wk before the surgical staging. RESULTS: Metastatic mediastinal lymph nodes were found in 35 patients. (99m)Tc-Tetrofosmin imaging in assessing the mediastinal involvement yielded a sensitivity of 85.7%, a specificity of 89.6%, and an accuracy of 88.0%; CT results were 68.6%, 75.0%, and 72.3%, respectively. SPECT accuracy was significantly higher than CT accuracy (P < 0.05). However, precise anatomic localization of (99m)Tc-tetrofosmin uptake in the mediastinum was not always present on SPECT images. (99m)Tc-Tetrofosmin SPECT precisely detected the presence or absence of lymph node metastases in 33 of the 36 patients with positive CT findings (enlarged mediastinal nodes with a short axis > or =1 cm), with an accuracy (91.7%) significantly higher (P < 0.05) than that of CT (66.7%). CONCLUSION: (99m)Tc-Tetrofosmin SPECT is a useful presurgical noninvasive method to assess mediastinal lymph node involvement in NSCLC. In particular, it could play a clinical role in reducing the number of invasive staging surgical procedures in selected patients, especially in those with enlarged lymph nodes at CT. Fusing SPECT with CT images could further improve the interpretation of the scintigraphic data.     

Acute left ventricular filling time and rate changes in hypertrophic cardiomyopathy after verapamil and propranolol evaluated by nuclear stethoscope

We have undertaken the present study to evaluate the acute effects of propranolol and verapamil on the diastolic function in patients with hypertrophic cardiomyopathy. We used a non imaging isotope device, the nuclear stethoscope, that has been so far mainly employed for assessment of systolic function, although fitted for detecting diastolic filling rates and times as well. Relative cardiac output, ejection fraction, rapid and slow filling times and rates were measured in five patients suffering from hypertrophic cardiomyopathy in basal conditions and 10.20 and 30 minutes after i.v. administration for either propranolol or verapamil, with a time interval of at least 24 hours between the two acute drug studies. With respect to the baseline values only verapamil showed a significant improvement in rapid and maximum filling rates, suggesting that diastolic function is more beneficially affected by Ca-entry blockers rather than beta-blockers in hypertrophic cardiomyopathy.     

Endocannabinoid system involvement in brain reward processes related to drug abuse.

Cannabis is the most commonly abused illegal drug in the world and its main psychoactive ingredient, delta-9-tetrahydrocannabinol (THC), produces rewarding effects in humans and non-human primates. Over the last several decades, an endogenous system comprised of cannabinoid receptors, endogenous ligands for these receptors and enzymes responsible for the synthesis and degradation of these endogenous cannabinoid ligands has been discovered and partly characterized. Experimental findings strongly suggest a major involvement of the endocannabinoid system in general brain reward functions and drug abuse. First, natural and synthetic cannabinoids and endocannabinoids can produce rewarding effects in humans and laboratory animals. Second, activation or blockade of the endogenous cannabinoid system has been shown to modulate the rewarding effects of non-cannabinoid psychoactive drugs. Third, most abused drugs alter brain levels of endocannabinoids in the brain. In addition to reward functions, the endocannabinoid cannabinoid system appears to be involved in the ability of drugs and drug-related cues to reinstate drug-seeking behavior in animal models of relapse. Altogether, evidence points to the endocannadinoid system as a promising target for the development of medications for the treatment of drug abuse.     

Effect of 3,4-methylendioxymethamphetamine (MDMA, "ecstasy") on dopamine transmission in the nucleus accumbens shell and core

It is known that most of drugs abused by humans preferentially stimulate dopamine transmission in the shell subdivision of the nucleus accumbens as compared to the core. The aim of the present study was to evaluate whether this applies also to intravenous 3,4-methylendioxymethamphetamine (MDMA, "ecstasy") administered at doses that sustain self-administration behavior in rats. The effect of 0.32, 0.64, 1.0, 2.0 and 3.2 mg/kg i.v. of MDMA on dopamine transmission in the nucleus accumbens shell and core was studied in freely moving rats by means of dual probe microdialysis. MDMA dose-dependently stimulated dopamine transmission both in the shell and in the core but the increase in the shell was more pronounced compared to the core at doses of 0.64, 1.0 and 2.0 mg/kg. The increase of dialysate dopamine obtained after 0.32 mg/kg and after 3.2 mg/kg was not significantly different in the shell compared to the core of nucleus accumbens. This study extends to MDMA the property of other drugs of abuse to increase preferentially nucleus accumbens shell dopamine.