5-HYDROXYTRYPTAMINE-INDUCED CONTRACTION OF THE MARMOSET AORTA IS MEDIATED BY A 5-HT1-LIKE RECEPTOR

1. 5-Hydroxytryptamine (5-HT) exerts both contractile and relaxant effects in the marmoset isolated aorta, actions that are unaffected by the 5-HT₂ antagonist ketanserin. The aim of the present study was to define the receptors mediating the contractile activity of 5-HT in the marmoset aorta.
2. Contractile responses were elicited in aortic rings that were either: (i) precontracted submaximally with the thromboxane A₂ agonist U44069 in order to amplify the responses; or (ii) exposed to N ^ω-nitro- L -arginine (100 μmol/L) plus LY 53857 (0.1 μmol/L; a 5-HT₂ receptor antagonist shown previously to inhibit relaxation). The effect of 5-HT on adenosine 3',5'-cyclic monophosphate (cAMP) formation was also investigated.
3. The effects of agonists and antagonists comprised: (i) agonist potencies in the order 5-carboxamidotryptamine > 5-HT > sumatriptan > 8-hydroxy-2-(di- n -propylamino)tetralin; (ii) inhibition of contractile action of 5-HT by the 5-HT_1D antagonist GR 127935; (iii) a contractile response to methysergide; (iv) a lack of effect of tropisetron, an antagonist of 5-HT₃ and 5-HT₄ receptors; and (v) inhibition of forskolin-stimulated cAMP formation by 5-HT (in the presence of LY 53857), indicative of negative coupling to adenylate cyclase.
4. The above effects fulfil the criteria for a 5-HT₁-like receptor. In view of the previous finding that this contractile response is insensitive to ketanserin, it is concluded that the contractile effects of 5-HT in the marmoset aorta are mediated exclusively by a 5-HT₁-like receptor.     

Uptake and Killing of Mima polymorpha and Herellea vaginicola by the Reticuloendothelial System of Neonatally Thymectomized Nonwasted Mice

Phagocytosis and killing of Mima polymorpha and Herellea vaginicola by the liver, lungs, spleen, and kidneys from neonatally thymectomized nonwasted mice and their sham-thymectomized litter mates were compared. The removal of M. polymorpha from blood by these organs, measured 2 and 4 hr after intravenous injection of bacteria, was not affected by thymectomy. Because significantly fewer viable organisms persisted in the liver, spleen, and kidneys, it is concluded that bacterial killing increased after thymectomy. Phagocytosis of M. polymorpha by peritoneal macrophages increased in thymectomized mice. Removal of H. vaginicola from the blood by the lungs was greater after thymectomy. Thymectomy did not affect the killing of H. vaginicola by the liver, spleen, lungs, or kidneys. Killing of H. vaginicola by the kidney was less than that by other organs, although this was not affected by thymectomy. Chronic reticuloendothelial stimulation associated with infection was not an adequate explanation for these findings because no wasting syndrome was encountered.     

Modified calcaneal index: a new screening tool for osteoporosis based on plain radiographs of the calcaneum

PURPOSES: To assess osteoporosis using plain radiography of the calcaneum by studying the performance characteristics of the modified calcaneal index through inter- and intra-observer agreement. To study the correlation of the modified calcaneal index to quantitative ultrasound of the calcaneus and bone mineral density (BMD) of the femoral neck and distal radius. METHODS: Lateral calcaneal radiographs of 252 women who participated in a clinical trial for osteoporosis were reviewed. The BMD of the hip and distal radius was measured and the calcanea were assessed using ultrasound. The calcaneal radiographs were graded by 3 clinicians according to a previously described 5-grade calcaneal index. A modified 3-grade calcaneal index was then developed. RESULTS: The highest scores of intra- and inter-observer reliability of the modified calcaneal index were 0.45 and 0.40, respectively, which were higher than those of the 5-grade calcaneal index. The correlation of the modified calcaneal index with other measures was significant (hip BMD, r=0.31; distal radius BMD, r=0.28; calcaneal speed of sound, r=0.20; broadband ultrasound attenuation, r=0.36) [p<0.005]. There were significant differences in hip BMD, distal radial BMD, calcaneal speed of sound, and broadband ultrasound attenuation between the 3 grades of the modified calcaneal index (Kruskal-Wallis 1-way ANOVA; p<0.0001). CONCLUSION: The modified calcaneal index can be used to measure bone structure and skeletal strength and is a suitable screening tool for osteoporosis in places where advanced approaches to bone-status assessment are not available.     

Neuroimaging and personality disorders

Within the past several years, neuroimaging research on personality disorders has begun to develop. Personality disorders can be thought of as trait-like dysfunctional patterns in cognitive, affective, impulse control, and interpersonal domains. These domains of dysfunction have been linked to specific neural circuits. Developments in brain imaging techniques have allowed researchers to examine the neural integrity of these circuits in personality-disordered individuals. This article reviews the neuroimaging literature on borderline personality disorder, antisocial personality disorder (including psychopathy) and schizotypal personality disorder. Functional and structural studies provide support for dysfunction in fronto-limbic circuits in borderline and antisocial personality disorder, whereas temporal lobe and basal striatal-thalamic compromise is evident in schizotypal personality disorder.     

A case of lymphomatoid granulomatosis masquerading as a lung abscess

Lymphomatoid granulomatosis (LG) is a rare T cell rich, B cell non-Hodgkin's lymphoma which is difficult to diagnose. We present a patient with LG who demonstrated many of the difficulties in diagnosis and highlighted the importance of reviewing the diagnosis if treatment does not have the anticipated effect.