An analysis of theα-adrenoceptor modulation of vasomotor tone at the level of lateral medullary pressor area (LMPA)

Summary Microinjection of noradrenaline and clonidine into lateral medullary pressor area (LMPA) of chloralose anaesthetized cats produced dose dependent decrease in blood pressure without affecting heart rate, while phenylephrine did not elicit any cardiovascular response. Selective ₂-adrenoceptor, antagonists idazoxan and piperoxan, microinjected locally, blocked the effects of the agonists but prazosin and phenoxybenzamine, which are relatively selective for ₁-adrenoceptors, failed to do so. Clonidine did not elicit any response in guanethidine pretreated cats but noradrenaline microinjected into LMPA of these animals induced a pressor response which was blocked by prazosin pretreatment. It is concluded that catecholaminergic fibres impinging upon this are inhibit the activity of the inhibitory second order baroreceptor neurone by activating ₁-adrenoceptors while ₂-adrenoceptors situated presynaptically on these inhibitory catecholaminergic nerve terminals are responsible for the manifestation of the hypotensive effect of clonidine and exogenously administered noradrenaline.     

Anhidrotic ectodermal dysplasia presenting as atrophic rhinitis and epistaxis—A case report and light microscopic study

An interesting case of anhidrotic ectodermal dysplasia which came with ozaena, epistaxis, headache and maggots is presented. Histopathology of nasal mucosa, scalp and forearm skin, and a pilocarpine sweat test helped to confirm the diagnosis. In the present state of our knowledge, this X-linked recessive condition has no cure but symptomatic treatment along with heat potection and protection of the eyes has a role to play in the management of these cases. It is hoped that a forgotten cause of atrophic rhinitis is resurrected.     

Nucleus locus coeruleus: Evidence for α1-adrenoceptor mediated hypotension in the cat

Summary The Bezold-Jarisch reflex characterized by hypotension and bradycardia was elicited in anaesthetized artificially respired dogs (pretreated with a beta-adrenoceptor antagonist) using capsaicin 10 g/kg (i.v.). Intracisternal administration of the highly selective clonidine-like alpha₂ adrenoceptor agonists B-HT 920 (10 g/kg) or B-HT 933 (30 g/kg) significantly facilitated this reflex bradycardia. The involvement of central alpha₂-adrenoceptors is suggested as intracisternal administration of the alpha₂ adrenoceptor blocking drugs yohimbine (50 g/kg) and piperoxan (50 g/kg) antagonized this facilitation. B-HT 920 also facilitated the vagally mediated baroreceptor reflex to the hypertensive effect of intravenous noradrenaline (3 g/kg). Although the Bezold-Jarisch reflex and the baroreceptor reflex have different afferent pathways, both reflexes may either converge into a common pathway or have separate neuronal chains within the medulla; however, this study indicates that both have a similar central modulatory system stimulated by alpha₂ adrenoceptors.     

Eosinophilic Granuloma of the temporal bone

Primary Eosinophilic Granuloma of the temporal bone is a rare condition. A case is reported with review of relevant literature.     

Splenic abscess following blunt abdominal trauma

A rare case of splenic abscess occurring after blunt abdominal trauma in a previously healthy boy is reported. The diagnosis was made by ultrasonography. The patient recovered after splenectomy and drainage of subphrenic and intraperitoneal pus.     

Pseudoaneurysm of the superficial femoral artery following accidental trauma: result of treatment by percutaneous stent-graft placement

Accidental trauma frequently involves the extremities, and can extend to involve their blood supply, causing exsanguinating hemorrhage and pseudoaneurysm in the involved blood vessel. This is traditionally managed by surgical repair. We report a case in which control of life-threatening hemorrhage and exclusion of a large, post-traumatic pseudoaneurysm in the superficial femoral artery was performed by a commercially available stent-graft, without complication. This treatment method may be a safe and effective alternative to surgery in selected patients. Received: 10 February 1998; Revision received: 31 March 1998; Accepted: 20 April 1998     

Immunohistological localisation of vascular endothelial growth factor in human endometrium.

Several polypeptide growth factors regulate epithelial and stromal development in endometrium under the influence of estrogen and progesterone, and thereby regulate growth and differentiation of endometrium during menstrual cycle. However, little is known about the angiogenic growth factors that may affect endometrial vasculature throughout each menstrual cycle. Vascular endothelial growth factor (VEGF) is suggestively an important angiogenic growth factor in the female reproductive tract. The aim of the present study was to immunolocalize and assess semi-quantitatively VEGF immunostaining in cells of proliferative phase (n = 3), secretory phase (n = 6) and hyperplastic (n = 6) human endometrial samples. VEGF concentrations were significantly higher in glandular (P < 0.001) and stromal (P < 0.01) compartments of proliferative stage endometrium compared with those in secretory stage and hyperplastic endometrial samples, with no difference in the scores for glandular and stromal compartments between secretory stage and hyperplastic endometrial samples. Generally, glandular expression of VEGF was higher as compared to stromal compartment. Thus, it appears that endometrial VEGF expression and concentration are enhanced by estrogen, and may be correlated with neovascularization and increased vascular permeability during late proliferative period. Additionally, there was no enhancement in VEGF expression in hyperplastic glands, suggesting that regulation of glandular growth and that of angiogenesis in human endometrium operate through different mechanisms.     

Effects of a hybrid recombinant human alpha interferon (A/D) on in vitro cytotoxicity and in vivo localization of monoclonal antibody L6-cytosine deaminase conjugate in a colon cancer model

L6 is an IgG2a murine monoclonal antibody which we have demonstrated binds well to HT29 human colon carcinoma cells by flow cytometry, whole cell ELISA, and mixed hemadsorption. In vitro cytotoxicity studies revealed that the monoclonal antibody L6-cytosine deaminase (L6-CD) immunoconjugate plus the nontoxic prodrug, 5-fluorocytosine (5-FC), is equivalent to 5-fluorouracil (5-FU) in its ability to kill HT29 cells. Human alpha-interferon (A/D) was able to enhance this cytotoxic effect. The I.C.50's revealed that very small amounts of L6-CD are needed for this cytotoxic effect (approximately, 5 pg/ml resulted in 50% viability). The limiting factor was the amount of 5-FC employed with L6-CD (3 microM yielded 50% cell viability). alpha-Interferon (A/D) lowered the requirement of 5-FC to 1 microM to achieve 50% cell lethality. In vivo biodistribution experiments indicated that 1 microgram of L6-CD is nonspecifically taken up by the liver and spleen and cleared rapidly from the blood. Significant localization of L6-CD to HT29 tumors occurred only when 99 micrograms of unlabeled L6-CD was added to 1 microgram of 125I-labeled immunoconjugate injected intravenously. Further augmentation of tumor/blood ratios without reduction in percent injected dose per gram of tumor was possible with the intravenous injection of 100 micrograms of anti-idiotypic monoclonal antibody 13B, 24 hours after L6-CD, which bound unreacted L6-CD and cleared it from the blood. The addition of 100,000 U of alpha-interferon (A/D) given intraperitoneally every day increased the clearance of L6-CD by the liver and spleen, but impaired tumor localization (percent injected dose per gram). These studies demonstrated that in vivo localization of the L6-CD conjugate to HT29 tumors could be optimized by injecting excess L6-CD followed by an equal amount of L6 anti-idiotype mAb 13B, 24 hours after L6-CD.     

Evidence for central histaminergic mechanism in foot shock aggression

The role of central histaminergic system in foot shock induced aggression was studied in mice. Histamine administered by intracerebral (IC) injection (25–200 g) produced a significant increase in fighting episodes in a dose dependent manner. It was observed that mepyramine (H₁ blocker) given intraperitoneally (IP) significantly increased and metiamide (H₂ blocker) given IC decreased significantly the fighting response. To determine the nature of receptors involved in histamine induced facilitation of aggressive behaviour, histamine was administered IC in mice pretreated with mepyramine or metiamide. Mepyramine pretreatment further increased the facilitatory effect of histamine while metiamide blocked the enhancement of aggressiveness by histamine. Combined pretreatment with metiamide and mepyramine decreased significantly the fighting counts which remained unaffected after histamine. Haloperidol did not block the enhancement of aggression by histamine or mepyramine. However, atropine pretreatment partially inhibited the histamine induced increase in the fighting counts. Results of pretreatment with metiamide and atropine were similar to those obtained with pretreatment of metiamide and mepyramine. Metiamide alone or in combination with atropine failed to affect the facilitatory effect of amphetamine on the foot-shockaggression. It is concluded that central histamine H₂ receptors have a facilitatory role and H₁ receptors an inhibitory role on aggressive behaviour in mice induced by foot-shock. Since histamine per se had a facilitatory effect on foot-shock induced aggression, the central H₂ receptors seem to dominate over the H₁ receptors.