Radiation dose reduction during hysterosalpingography: an application of scanning-beam digital radiography

Hysterosalpingography was performed in 31 patients by means of a low-dose scanning-beam digital radiographic system. The technique permits adequate evaluation of gynecologic abnormalities while allowing significant reduction in radiation: 2.4-mR (6.1 X 10(-7) C/kg) exposure to the skin and 0.7-mrad (7 X 10(-6) Gy) mean dose to the ovaries per image obtained. Sixteen patients demonstrated readily recognizable and documented abnormalities, corroborated by laparoscopy, laparotomy, or other supportive evidence.     

Activation of 5-HT3 receptor by 1-phenylbiguanide increases dopamine release in the rat nucleus accumbens

The serotonin-3 (5-HT₃) agonist 1-phenylbuguanide (0.1–1.0 mM in perfusate) caused a robust, dose-dependent enhancement of extracellular dopamine content in nucleus accumbens as measured by in vivo microdialysis. This action was antagonized by co-perfusion of the 5-HT₃ antagonists zacopride and GR38032F (1 mM in perfusate). Similar effects were observed in 5-HT-denervated rats. These findings suggest that there is a potent modulation of dopamine (DA) release in the nucleus accumbens mediated via 5-HT₃ receptors, which appear to be located presynaptically on DA terminals of the mesolimbic DA pathway.     

Cardioprotective effects of diltiazem when given before, during or delayed after infusion of norepinephrine in anesthetized dogs

Catecholamine excess has been shown to produce 2 distinct forms of irreversible myocardial necrosis termed contraction band lesions. Calcium channel blocking agents provided a variable protective effect from these contraction band lesions. The purpose of this study was to determine the temporal responses of the most effective of these blocking agents, diltiazem, when given before, simultaneous with or after an initial exposure to a necrogenic infusion of norepinephrine (NE). Forty-one adult mongrel dogs were anesthetized with sodium pentobarbital (32 mg/kg) and infused with saline solution or NE (4 micrograms/kg/min) for 60 minutes or diltiazem at a rate of 20 micrograms/kg/min for the first 5 minutes and 10 micrograms/kg/min for the remaining 70 minutes. Diltiazem was infused as pretreatment 15 minutes before continued infusion with NE for 60 minutes, simultaneously infused with NE for 60 minutes or delayed 30 minutes after the start of NE infusion. Diltiazem alone exhibited no significant effect on hemodynamics, but pretreatment with diltiazem was able to moderate the rapid NE-induced increases in heart rate. NE infusion produced significant numbers of the 2 forms of contraction band lesions: (1) paradiscal contraction band lesions involving a small portion of the cell adjacent to the disc, and (2) holocytic contraction band lesions involving the entire cell. Diltiazem reduced the number of contraction band lesions, particularly the holocytic contraction band lesions, provided diltiazem was available before the insult and massive influx of calcium with a pharmacologic dose of NE. Although the exact mechanism of diltiazem's cardioprotective properties is not known, the timing of drug administration does appear to affect the degree of protection.     

Solitary bronchioloalveolar carcinoma: CT criteria

The computed tomographic (CT) scans of 30 patients with solitary bronchioloalveolar carcinoma were reviewed. Common features at CT included the peripheral or subpleural location of a pulmonary mass (25 cases), pseudocavitation (18 cases), heterogeneous attenuation (17 cases), irregular margins forming a star pattern (22 cases), and pleural tags (21 cases). Using these CT criteria, four independent observers attempted to identify cases of bronchioloalveolar carcinoma from a larger sample of lung cancers and benign lesions by categorizing a series of test cases into four probability categories. Although the bronchioloalveolar carcinomas were correctly ranked in the two highest probability categories 75% of the time (in 45 of 60 cases), there was considerable overlap with other lung lesions, particularly with adenocarcinoma and large cell undifferentiated carcinoma. However, even though the typical features of bronchioloalveolar carcinoma are not invariable or highly specific, they are characteristic enough to suggest the diagnosis.