The relationship between basal and acute HPA axis activity and aggressive behavior in adults

The hypothalamic–pituitary–adrenal (HPA) axis seems to play a major role in the development, elicitation, and enhancement of aggressive behavior in animals. Increasing evidence suggests that this is also true for humans. However, most human research on the role of the HPA axis in aggression has been focusing on highly aggressive children and adolescent clinical samples. Here, we report on a study of the role of basal and acute HPA axis activity in a sample of 20 healthy male and female adults. We used the Taylor Aggression Paradigm to induce and measure aggression. We assessed the cortisol awakening response as a trait measure of basal HPA axis activity. Salivary free cortisol measures for the cortisol awakening response were obtained on three consecutive weekdays immediately following awakening and 30, 45, and 60 min after. Half of the subjects were provoked with the Taylor Aggression Paradigm to behave aggressively; the other half was not provoked. Acute HPA axis activity was measured four times, once before and three times after the induction of aggression. Basal cortisol levels were significantly and negatively related to aggressive behavior in the provoked group and explained 67% of the behavioral variance. Cortisol levels following the induction of aggression were significantly higher in the provoked group when baseline levels were taken into account. The data implicate that the HPA axis is not only relevant to the expression of aggressive behavior in clinical groups, but also to a large extent in healthy ones.     

Differential effects of dopamine agonists upon stimulated limbic and striatal dopamine release: in vivo voltammetric data.

1. Fast cyclic voltammetry at carbon fibre microelectrodes was used in rats anaesthetized with chloral hydrate to monitor dopamine release in the caudate and nucleus accumbens evoked by electrical stimulation of the median forebrain bundle. Stimulation trains (50 Hz sinusoidal current, 100 +/- 10 microA r.m.s., 2s duration) were repeated every 5 min throughout the experiment. 2. The actions of the dopamine agonists quinpirole, pergolide, SKF 38393, bromocriptine, (+)-3-(3-hydroxyphenyl)-N-n-propylpiperidine ((+)-3PPP) and (-)-3PPP were compared in the two nuclei. 3. Bromocriptine (10 mg kg-1, i.p.) did not affect release in either nucleus while SKF 38393 caused a fleeting decrease in limbic but not striatal dopamine release at a high dose (20 mg kg-1, i.p.). 4. Quinpirole and pergolide (both 1 mg kg-1, i.p.) decreased stimulated dopamine release in the nucleus accumbens while in the caudate the drugs each caused a transient, though not quite significant, elevation of stimulated dopamine release followed by decrease in release of the same magnitude as that seen in the nucleus accumbens. 5. The (-)-enantiomer of 3PPP (20 mg kg-1, i.p.), a partial agonist at the dopamine autoreceptor, increased stimulated dopamine release in both nuclei although the action in the caudate was larger and more prolonged. (+)-3PPP (20 mg kg-1, i.p.), a full agonist, decreased release in the nucleus accumbens. A small, transient and not significant increase in the caudate was followed by decreased release. 6. The results are interpreted as being evidence for differences in the dopamine autoreceptor in the two nuclei, possibly in the affinity state of the receptor in each nucleus.     

Complications of transluminal angioplasty

Four hundred fifty-three percutaneous transluminal angioplasties in 352 patients were reviewed to determine the frequency, distribution, and cause of complications. The primary success rate was 89% (81%-82% for renal and distal runoff vessels, 91%-95% for the iliofemoral arteries). Fifty-nine complications occurred in 53 patients, including 20 puncture site complications, the most frequent being hematoma. The most important angioplasty complication was acute occlusion of the arterial lumen attributed to acute thrombosis (2%). Subintimal passage of the guide wire/catheter (2%) may also cause luminal compromise. Arterial dissection following balloon dilatation (1%) and distal emboli (1.5%) were less important clinically, and vessel wall rupture was rare (0.4%). Complications were two to four times more frequent for renal and distal popliteal/tibial compared with iliofemoral angioplasties; the lower success and higher complication rates are attributed to greater technical difficulty and the increased importance of spasm. Operator experience and technical refinements play an important role in reducing occurrence of serious complications. The frequency and severity of angioplasty complications compare favorably with the alternative surgical procedure.     

Nondilated obstructive uropathy: percutaneous nephrostomy performed to reverse renal failure

Ureteral obstruction can lead to renal failure without involving detectable dilatation of the calyces, renal pelvis, or ureter proximal to the obstruction. This phenomenon was noted in seven patients who had clinical obstruction that we were not able to diagnose using computed tomography (CT) or ultrasonography (US). These patients underwent percutaneous nephrostomy (PCN), which resulted in brisk diuresis and improved renal function. We obtained an accompanying antegrade urogram in these cases, which demonstrated the level of obstruction and indicated that dilatation of the collecting system was minimal or not present. When obstructive uropathy is suspected, we believe it is essential to consider performing PCN to evaluate and potentially reverse renal failure, even when CT and US scanning do not demonstrate obstruction.     

Anterior diaphragm: variations in the CT appearance

The anterior portion of the diaphragm has three typical appearances on computed tomographic (CT) scans, depending on the cephalocaudal relation of the xiphoid to the central tendon of the diaphragm. The anterior diaphragm most often appears as a relatively smooth or slightly undulating soft-tissue curve, concave posteriorly and continuous across the midline with the lateral diaphragmatic arcs. In the next most frequent CT appearance, the diaphragmatic line is discontinuous in the midline. On each of these images, the muscular line diverges rather than converges as it approaches the anterior chest wall. Less commonly, the anterior portions of the diaphragm are imaged on CT not as a thin line but instead as a broad band with irregular, ill-defined, or angular margins. Occasionally, the anterior diaphragmatic muscle is not identified on CT because the muscle fibers are inseparable from adjacent structures, or are extremely short or even absent. An understanding of these anatomic variations permits the correct diagnosis of Morgagni hernias and explains previously described variants of plain radiographic configurations of pneumoperitoneum.     

Inflammation: imaging with Tc-99m HMPAO-labeled leukocytes

Leukocytes labeled with technetium-99m hexamethylpropyleneamine oxime (HMPAO) were used in 100 patients: 32 with suspected inflammatory bowel disease, 17 with fever of unknown origin, 21 with suspected abdominal sepsis, 20 with suspected bone sepsis, seven with bronchiectasis, and three with recent myocardial infarction. The distribution of activity in patients subsequently shown not to have inflammatory bowel disease was similar to that previously described for indium-111-labeled leukocytes. However, in this study, activity was also seen in the kidneys and bladder and occasionally the gallbladder on both early (1-3 hours) and late (24 hours) views, and in the colon in late views. Migration of Tc-99m-labeled granulocytes was seen in inflammatory disease as early as 30 minutes after injection, while normal bowel activity was not seen before 4 hours. The sensitivity of Tc99m-labeled leukocytes in the detection of inflammation was 100%, the specificity was 95%.     

Intraocular tumors: evaluation with MR imaging

Sixty-seven ocular tumors were studied with magnetic resonance (MR) imaging and computed tomography (CT). These tumors included primary uveal melanoma (n = 55), circumscribed choroidal hemangioma (n = 3), diffuse choroidal hemangioma (n = 1), retinal capillary hemangioma (n = 1), medulloepithelioma (n = 1), choroidal nevus (n = 1), retinoblastoma (n = 1), and choroidal metastases (n = 4). MR imaging demonstrated all these lesions, while CT demonstrated 88%. Associated retinal detachment was more easily distinguished from the neoplasms with MR imaging. Extrascleral extension of melanoma and hemorrhagic cystic necrosis within the melanoma were clearly demonstrated with MR imaging, but not with CT. Ninety-three percent of melanomas were markedly hyperintense, compared with the intensity of the vitreous body, on T1-weighted images and hypointense on T2-weighted images. All metastatic lesions were isointense on T1-weighted images and hypointense on T2-weighted images. The circumscribed choroidal hemangiomas were hyperintense on T1-weighted images and isointense on T2-weighted images. MR imaging is superior to CT in detection of intraocular tumors and may be more specific in diagnosis.