Inhibition of vagal vasodilatation by a selective neuropeptide Y Y2 receptor agonist in the bronchial circulation of anaesthetised dogs

Neuropeptide Y (NPY) is both co-stored and co-released with noradrenaline from sympathetic nerve terminals. In the cardiovascular system, NPY acts on two main receptor subtypes. At postjunctional, or Y1 receptors, NPY can cause both direct vasoconstriction and the potentiation of various constrictor agents. NPY acting at the presynaptic, or Y2 receptor, inhibits the release of neurotransmitter from autonomic nerves. In the present paper, we have used both sympathetic stimulation and the selective NPY Y2 receptor agonist, N-acetyl [Leu28,Leu31] NPY24-36, to examine the role of NPY in the inhibition of vagally mediated vasodilatation in the bronchial circulation of the anaesthetised dog. Stimulation of the cardiac end of the cervical vagus nerve at 1 Hz for 15 s (1 ms, 70 V) increased bronchial vascular conductance by 45%. This increase in flow was abolished by atropine. Sympathetic stimulation for 2.5 min at 16 Hz (1 ms, 20 V) produced a significant (P < 0.05) and prolonged (9 min) inhibition of the subsequent parasympathetically evoked vasodilatation. Similarly, the NPY Y2 receptor agonist, N-acetyl [Leu28,Leu31] NPY24-36, produced a significant (P < 0.05) and prolonged (15 min) inhibition of parasympathetically evoked vasodilatation. When vagus was stimulated at 2.5 Hz for 30 s (1 ms, 70 V), an atropine-resistant, but capsaicin-sensitive vasodilatation was observed. Neither sympathetic stimulation nor the NPY Y2 receptor agonist could be demonstrated to inhibit this vasodilatation. These results suggest that NPY can inhibit cholinergic parasympathetic vasodilatation in the bronchial circulation by an action on NPY Y2 receptors.     

Renographic indices for evaluation of changes in graft function

Radionuclide renal diagnostic studies play an important role in assessing renal allograft function, especially in the early post-transplant period. In the past two decades various quantitative parameters have been derived from the radionuclide renogram to evaluate changes in perfusion and/or function of the kidney allograft. In this review article we discuss the quantitative parameters that have been used to assess graft condition, with emphasis on the early postoperative period. These quantitative methods are divided into parameters used for assessing renal graft perfusion and parameters used for evaluating parenchymal function. The blood flow in renal transplants can be quantified (a) by measuring the rate of activity appearance in the kidney graft, (b) by calculating the ratio of the integral activity under the transplanted kidney and arterial curves and (c) by calculating the renal vascular transit time. In this article we review a number of parenchymal uptake and excretion indices, such as the accumulation index, the graft uptake capacity at 2 and 10 min, the excretion index and the elimination index. The literature on these parameters shows that they have some practical disadvantages. In addition, values suffer from significant overlap when various graft pathologies coexist. A retrospective study was designed in our institution to evaluate the clinical usefulness of some of the frequently used previously published methods in which the graft function is quantitatively assessed in the early post-transplant period. The quantitative parameters studied which were reasonably reproducible in our hands included: global perfusion index (GPI), cortical perfusion index (CPI), vascular transit time, and the parenchymal parameters uptake capacity at 2 min (UC2) and elimination index (K3/20). The patient population in this study consisted of 43 patients with 157 technetium-99m mercaptylacetyltriglycine renograms. The perfusion indices GPI and CPI did not allow differentiation of the acute tubular necrosis (ATN) group from the acute rejection (AR) group; however, they were of value in monitoring the improvement in the condition of the graft dysfunction in both the AR and ATN groups. As for the parenchymal parameters, both UC2 and K3/20 were able to differentiate stable graft function (SGF) versus AR and ATN groups but were unable to separate AR from ATN dysfunction. The ability of these parenchymal parameters to detect improvement in the graft function was poor and statistically non-significant. From the literature data and our own findings it is concluded that radionuclide scintigraphy of renal transplants has assumed an important role, especially if performed serially, in monitoring graft function in the post-transplant period. Many quantitative parameters have been derived from the radionuclide renogram to evaluate changes in perfusion and/or function of the kidney allograft. It appears that these quantitative numerical values are unable to differentiate unequivocally between grafts with ATN and AR cases. The real value of these parameters lies in the follow-up of the dysfunction processes, which helps the clinician to determine the appropriate therapeutic regimen.     

Three-dimensional CT angiography of the thorax: clinical applications

Spiral CT with three-dimensional (3D) display can provide a rapid noninvasive examination of the vascular system and has been shown to have a wide range of clinical applications in the thorax, including imaging of the aorta, pulmonary vasculature, and venous abnormalities. Three-dimensional images can provide views of the imaging volume from innumerable viewing angles for both the radiologist and referring clinician, and potentially obviate invasive procedures such as angiography. In this article, we will review many of these applications of spiral CT angiography with 3D displays. Emphasis is placed on study design, protocol selection, and display of pathology.     

Intratumoral cisplatin/epinephrine-injectable gel as a palliative treatment for accessible solid tumors: a multicenter pilot study

Intratumoral injections of cisplatin/epinephrine-injectable gel were administered weekly for 4 weeks in 45 patients with malignant tumors of various histologic types. Tumors were located on the skin and subcutaneous tissue primarily of the head, neck, and trunk, and on the tongue, oral pharynx, and esophagus. Patients were not candidates for surgery, radiation, or systemic chemotherapy. Each of the treated tumors (n = 82) was evaluated 2, 4, 8, and 12 weeks after the final injection. The initial dose of cisplatin was 1 mg/cm3 tumor volume, with escalation to 6 mg/cm3 allowed, depending on observed toxicities. The mean cumulative dose per patient for the four treatments ranged from 0.56 to 380 mg cisplatin. No dose-limiting cisplatin-related toxicities, such as nephrotoxicity, neurotoxicity, or ototoxicity, were observed. The overall objective tumor response rate was 50% (41 of 82), with 40% (33 of 82) complete responses and a median response duration of 160 days. Complete responses for adenocarcinoma and squamous cell carcinoma were 58% (21 of 36) and 38% (12 of 32), respectively. These results justified further clinical trials to evaluate the role of local chemotherapy with intratumoral cisplatin/epinephrine-injectable gel in the palliative treatment of patients with selected accessible solid tumors.     

Calsenilin: a calcium-binding protein that interacts with the presenilins and regulates the levels of a presenilin fragment

Most early-onset familial Alzheimer disease (AD) cases are caused by mutations in the highly related genes presenilin 1 (PS1) and presenilin 2 (PS2). Presenilin mutations produce increases in beta-amyloid (Abeta) formation and apoptosis in many experimental systems. A cDNA (ALG-3) encoding the last 103 amino acids of PS2 has been identified as a potent inhibitor of apoptosis. Using this PS2 domain in the yeast two-hybrid system, we have identified a neuronal protein that binds calcium and presenilin, which we call calsenilin. Calsenilin interacts with both PS1 and PS2 in cultured cells, and can regulate the levels of a proteolytic product of PS2. Thus, calsenilin may mediate the effects of wild-type and mutant presenilins on apoptosis and on Abeta formation. Further characterization of calsenilin may lead to an understanding of the normal role of the presenilins and of the role of the presenilins in Alzheimer disease.     

Social behavior correlates of cortisol activity in child care: gender differences and time-of-day effects

The relations between social behavior and daily patterns of a stress-sensitive hormone production were examined in preschool children (N = 75) attending center-based child care. Three behavioral dimensions, shy/anxious/internalizing, angry/aggressive/externalizing, and social competence, were assessed by teacher report and classroom observation, and their relations with 2 measures of cortisol activity, median (or typical) levels and reactivity (quartile range score between second and third quartile values) were explored. Cortisol-behavior relations differed by gender: significant associations were found for boys but not for girls. Specifically, for boys externalizing behavior was positively associated with cortisol reactivity, while internalizing behavior was negatively associated with median cortisol. Time of day of cortisol measurement affected the results. Surprisingly, median cortisol levels rose from morning to afternoon, a pattern opposite to that of the typical circadian rhythm of cortisol. This rise in cortisol over the day was positively correlated with internalizing behavior for boys. The methodological and theoretical implications of these findings for the study of the development of hormone-behavior relations are discussed.     

Aortic dissection involving an aberrant right subclavian artery: CT and MR findings

Studies were conducted to determine the effect of environmental temperature on the susceptibility of Culex pipiens (L.) to Rift Valley fever (RVF) virus. Larval rearing temperature (13, 17, 19, or 26 degrees C) did not affect the susceptibility of adult female Cx. pipiens to infection with RVF virus. In contrast, the adult holding temperature after a viremic blood meal affected infection rates in females. Significantly fewer mosquitoes contained detectable virus when they were held at cooler temperatures, 13 degrees C (10%), 17 degrees C (20%), and 19 degrees C (41%) than at a warmer temperature, 26 degrees C (91%). For mosquitoes held at 13 degrees C and then switched to 26 degrees C, infection rates increased steadily with increased time at 26 degrees C. There was no effect on the ability to detect RVF virus in adult females that were subjected to cooler holding temperature (17 degrees C) after they were first held at warmer temperature (26 degrees C). The role of environmental temperature needs to be considered in studies on the epidemiology of arthropod-borne viruses.     

Swelling-induced arachidonic acid release via the 85-kDa cPLA2 in human neuroblastoma cells

Arachidonic acid or its metabolites have been implicated in the regulatory volume decrease (RVD) response after hypotonic cell swelling in some mammalian cells. The present study investigated the role of arachidonic acid (AA) during RVD in the human neuroblastoma cell line CHP-100. During the first nine minutes of hypo-osmotic exposure the rate of 3H-arachidonic acid (3H-AA) release increased to 250 +/- 19% (mean +/- SE, n = 22) as compared with cells under iso-osmotic conditions. This release was significantly inhibited after preincubation with AACOCF3, an inhibitor of the 85-kDa cytosolic phospholipase A2 (cPLA2). This indicates that a PLA2, most likely the 85-kDa cPLA2 is activated during cell swelling. In contrast, preincubation with U73122, an inhibitor of phospholipase C, did not affect the swelling-induced release of 3H-AA. Swelling-activated efflux of 36Cl and 3H-taurine were inhibited after preincubation with AACOCF3. Thus the swelling-induced activation of cPLA2 may be essential for stimulation of both 36Cl and 3H-taurine efflux during RVD. As the above observation could result from a direct effect of AA or its metabolite leukotriene D4 (LTD4), the effects of these agents were investigated on swelling-induced 36Cl and 3H-taurine effluxes. In the presence of high concentrations of extracellular AA, the swelling-induced efflux of 36Cl and 3H-taurine were inhibited significantly. In contrast, addition of exogenous LTD4 had no significant effect on the swelling-activated 36Cl efflux. Furthermore, exogenous AA increased cytosolic calcium levels as measured in single cells loaded with the calcium sensitive dye Fura-2. On the basis of these results we propose that cell swelling activates phospholipase A2 and that this activation via an increased production of AA or some AA metabolite(s) other than LTD4 is essential for RVD.