Feline upper respiratory tract lymphoma: site, cyto-histology, phenotype, FeLV expression, and prognosis.

Lymphoma is the most common feline upper respiratory tract (URT) tumor. Primary nasal and nasopharyngeal lymphomas have been evaluated as distinct pathological entities; however, data on their differing clinical behavior are missing. A total of 164 endoscopic- guided URT pinch biopsies were formalin fixed and routinely processed. Imprint cytological specimens were stained with May Grünwald-Giemsa. Immunohistochemistry for anti-CD20, CD3, FeLVp27, and FeLVgp70 was performed. Prognostic significance of clinicopathological variables was investigated by univariate and multivariate analysis. Lymphoma was diagnosed in 39 cats (24%). Most cats with lymphoma were domestic shorthair (32 [82%]), were male (F/M = 0.56), and had a mean age of 10.3 years (range, 1-16 years). Lymphomas were primary nasal in 26 cats (67%), nasopharyngeal in 6 (15%), and in both locations (combined lymphomas) in 7 cats (18%). Neoplastic growth pattern was diffuse in 35 cases (90%) and nodular in 4 (10%). Epitheliotropism was observed in 10 cases (26%). Tumor cells were large in 15 cases, were small and medium in 11 cases each, and 2 had mixed cell size. Submucosal lymphoplasmacytic inflammation was observed in 23 cases (59%). Cytology was diagnostic for lymphoma in 12 of 25 cases (48%). A B-cell origin prevailed (34 [87%]). Feline leukemia virus (FeLV) p27 or gp70 antigen was detected in 21 lymphomas (54%). URT lymphomas were aggressive, with survival varying from 0 to 301 days (mean, 53 days). Epitheliotropism in 8 B-cell lymphomas (80%) and in 2 T-cell lymphomas (20%) correlated with prolonged survival. Age younger or older than 10 years had a negative prognostic value. Lymphoplasmacytic inflammation and FeLV infection may represent favoring factors for URT lymphoma development.

Alpha 1 adrenoceptor subtype mediates noradrenaline induced contraction of the human internal mammary artery: radioligand and functional studies.

STUDY OBJECTIVE: The aim was to evaluate the characteristics of alpha adrenergic binding sites on human internal mammary arteries and the alpha adrenoceptor mediated vasoconstrictor response to catecholamines. DESIGN: Human internal mammary arteries were cut longitudinally, the intimal layer was scraped, and the arteries homogenised and centrifuged at 50,000 g to obtain a membrane pellet. Saturation isotherms with [3H]-prazosin were done with 50-100 micrograms plasma membranes per tube and increasing concentrations of [3H]-prazosin (non-specific binding: 2.5 mM noradrenaline plus superoxide dismutase and catalase). Kinetic isotherms were done with 100 micrograms plasma membranes and 1-5 nM [3H]-prazosin for time periods ranging from 1 to 90 min; at the equilibrium, dissociation of [3H]-prazosin was achieved by 10 microM prazosin. alpha 2 Adrenoceptor density on internal mammary artery membranes was assessed with [3H]-rauwolscine (non-specific binding: 1 microM yohimbine). Separation of membrane bound radioactivity was achieved by rapid vacuum filtration through Whatman GF/C fibre filters. Saturation isotherms were evaluated by Scatchard plots and kinetic data, and competition isotherms by Enzfitter analysis. Contractility studies were done with helical strips of artery (without adventitial layer) placed in a thermostated perfusion bath. Data were obtained in the presence of different concentrations of agonists and antagonist to obtain Schild plots. Antagonist drugs were employed at only one concentration for each preparation. SUBJECTS: Mammary arteries were collected from 51 patients (age range 42-65 years) undergoing surgery for coronary grafting. MEASUREMENTS AND MAIN RESULTS: The binding of [3H]-prazosin to arterial plasma membrane was rapid and reversible. The K + 1 was 0.13 (SD 0.03) X 10(9) M.min-1 (n = 5) and the Kd, determined as a ratio between k-1/K + 1, was 0.34(0.01) nM (n = 5). [3H]-Prazosin binding, displaceable by 2.5 mM (-)-noradrenaline, was saturable and disclosed an alpha 1 adrenoceptor density of 30(3) fmol.mg-1 protein with a dissociation constant (Kd) of 215(50) pM (n = 18). The adrenergic agonists competed with [3H]-prazosin in the following order of potency: (-)-adrenaline [Ki = 0.6(0.1) microM; n = 5] greater than (-)-noradrenaline [Ki = 1.05(0.015) microM; n = 12] much greater than (-)-isoprenaline [Ki = 150(10) microM; n = 4]. Specific binding of [3H]-rauwolscine to IMA plasma membranes was negligible (about 2 fmol.mg-1 protein) (n = 15) with an unfavourable ratio of non-specific v specific binding. Catecholamines induced a dose dependent contractile response in arterial strips; (-)-noradrenaline: EC50 = 0.48(0.12) microM, n = 20; (-)-adrenaline: EC50 = 0.15(0.16) microM, n = 10; and methoxamine, a selective alpha 1 adrenergic agonist: EC50 0.67(0.15) microM, n = 10. The alpha 2 adrenoceptor agonists BHT-933, BHT-920, and guanabenz did not contract the arterial strips (up to 10 mM). Prazosin (0.03-0.1 microM) produced concentration dependent right shifts of the (-)-noradrenaline [pA2 = 9.83(0.11), n = 19], (-)-adrenaline [pA2 = 9.50(0.31), n = 10], and methoxamine [pA2 = 8.96(0.18), n = 10] concentration-response curve. CONCLUSIONS - Internal mammary artery plasma membranes possess alpha 1 adrenoceptors which are involved in the vasoconstrictor response to catecholamines. alpha 2 Adrenoceptors seem not to be involved.

Pathological characterization of primary splenic myxoid liposarcomas in three dogs.

Non-angiomatous-non-lymphomatous sarcomas (NANLs) represent 23%-34% of canine primary splenic sarcomas. Splenic liposarcomas account for 2%-6% of NANLs but myxoid variants are rarely reported and information on their behaviour is fragmentary. An 8-year-old male crossbreed (case 1), a 12-year-old female French bulldog (case 2), and an 11-year-old crossbreed (case 3) underwent splenectomy after the detection of a splenic nodule. Histology, histochemistry, immunohistochemistry, and transmission electron microscopy (TEM) were performed. Bundles of spindle-to-polygonal cells containing occasional cytoplasmic oil-red-O positive vacuoles embedded in an Alcian blue-positive extracellular matrix were observed. Aggregates of round cells were detected in cases 1 and 3. All tumours were vimentin positive and actin, desmin, Factor VIII, and S100 negative. The TEM evidenced different maturational stages of adipose cells (lipoblasts, intermediate, and undifferentiated). All the cases developed hepatic metastases and were euthanized. Disease free interval was 2 months in cases 1 and 3, and 21 months in case 2. The presence of a neoplastic embolus in case 1 and areas of round cell differentiation in cases 1 and 3 represented the sole prognostic indices.

Alternative splicing of the estrogen receptor primary transcript normally occurs in estrogen receptor positive tissues and cell lines.

Several laboratories have described estrogen receptor mRNA variants created by skipping internal exons. Some of the putative proteins encoded for by these variants have been functionally characterized by transfection analyses. The variant lacking exon 5 would lead, if translated, to a truncated receptor which shows dominant positive transactivation activity in the absence of hormone. It has been postulated that the variant could account for anti-estrogen resistant tumor growth and for expression of the progesterone receptor in estrogen negative tumors. In order to understand the possible role this and other variants may have in the tumorigenesis of mammary tissue we have carried out a thorough analysis of variants expressed in a tumor cell line (MCF-7), in a tumor sample and in a sample of normal breast tissue derived from mammary reduction surgery. We performed rt-PCR analyses followed by hybridization with exon specific oligonucleotide probes. By these means we have detected nine different variants co-expressed in MCF-7 cells and at least the major variants were equally expressed in normal and neoplastic breast tissue. The same is true for the variant lacking exon 5 which, however, resulted to be a variant of low expression in the three samples analyzed. Variant formation appeared to be restricted to the estrogen receptor messenger since several other members of the superfamily of nuclear receptors did not show variant formation. We also have analyzed the effect of the most abundantly expressed variant, the exon 4 lacking variant, on normal estrogen receptor function, on the growth and on the response to estradiol and to tamoxifen of MCF-7 cells. Although over-expressed at high levels this variant has, if any, only marginal effects on the expression of endogenous estrogen regulated genes and on growth and response to the hormone and its antagonist. Although the lack of function of this variant cannot be extrapolated to other variants, their involvement in tumor formation appears rather unlikely since they are also expressed in normal tissue and the single variant is expressed in addition to many others, some of which might have opposing effects. Variant formation is, however, specific for the estrogen receptor and apparently regulated with tissue specificity as our expression analysis in normal mouse tissues shows. Therefore the variants probably have a physiological significance yet to be discovered.

Blockade of adenosine A2A receptors by SCH 58261 results in neuroprotective effects in cerebral ischaemia in rats.

Blockade of adenosine receptors can reduce cerebral infarct size in the model of global ischaemia. Using the potent and selective A2A adenosine receptor antagonist, SCH 58261, we assessed whether A2A receptors are involved in the neuronal damage following focal cerebral ischaemia as induced by occluding the left middle cerebral artery. SCH 58261 (0.01 mg/kg either i.p. or i.v.) administered to normotensive rats 10 min after ischaemia markedly reduced cortical infarct volume as measured 24 h later (30% vs controls, p < 0.05). Similar effects were observed when SCH 58261 (0.01 mg/kg, i.p.) was administered to hypertensive rats (28% infarct volume reduction vs controls, p < 0.05). Neuroprotective properties of SCH 58261 administered after ischaemia indicate that blockade of A2A adenosine receptors is a potentially useful biological target for the reduction of brain injury.

Role of 5-HT2 receptors in serotonin-induced contraction in the human mammary artery.

We studied the effects of serotonin (5-HT) on isolated human mammary arteries obtained from patients undergoing coronary by-pass grafting. 5-HT induced a concentration-dependent contractile response in the mammary artery, with an EC50 value of 0.34 microM. The 5-HT2 antagonist, ketanserin, reversed the contractions evoked by 5-HT in a competitive manner at a low concentration (10(-8) M), whereas non-competitive antagonism was apparent at higher concentrations (5 X 10(-8)-5 X 10(-7) M). To investigate whether the alpha 1-blocking component of ketanserin plays a role in the response observed in this vessel, we evaluated the effect of ketanserin on contractions induced by (-)-norepinephrine. Ketanserin, in concentrations up to 10(-7) M, did not influence the norepinephrine-induced contractions. Moreover, a threshold concentration of 5-HT (10(-7) M) amplified the contractile effect induced by norepinephrine (5 X 10(-8) M), and this response was inhibited by ketanserin (10(-7) M). The selective 5-HT3 antagonist, GR 38032F, did not affect the 5-HT-induced contractions. These findings indicate that the human mammary artery is a vascular tissue sensitive to 5-HT. The 5-HT2 receptor subtype appears to mediate the response.

Anticatabolic action of formebolone in the castrated rat treated with dexamethasone.

The anticatabolic action of 2-formyl-17a-methylandrosta-1,4-diene-11a,17beta-diol-3-one (formebolone) was demonstrated by assessing the nitrogen elimination in the urine of castrated rats treated with dexamethasone-21-phosphate. The absence of a virilizing action is duly pointed out.

Beta 1 and beta 2 adrenoceptors are involved in mediating vasodilation in the human coronary artery.

We have characterized beta-adrenoceptors in the human coronary artery and investigated the mechanism underlying vasodilating activity of dilevalol, a non-selective beta-blocking agent with beta 2 agonist properties. Specific [125I]-pindolol binding was saturable, reversible and of high affinity (Kd = 91 +/- 7 pM; Bmax = 10 +/- 3 fmol/mg protein). Competition curves of [125I]-pindolol in the presence of ICI 118,551, a selective beta 2 antagonist, or CGP 20712A, a selective beta 1 antagonist, were best explained by a two-site binding model (48 +/- 5% beta 1 and 52 +/- 4% beta 2 receptors). In isolated coronary strips, isoproterenol induced a dose-dependent vasorelaxant effect which was blocked by either ICI 118,551 (100 nM) or CGP 20712A (100 nM). Dilevalol produced about 30-40% of vasodilating activity starting at a concentration of 100 nM. The response was antagonized selectively by ICI 118,551 suggesting that dilevalol produces vasodilation through the stimulation of beta 2 receptors. These findings show that in the human coronary artery both beta 1 and beta 2 receptor subtypes are present and mediate vasodilation. This suggests that the human coronary artery could be used for the evaluation of the vasodilating component of new beta-adrenoceptor blocking agents.

Antihypertensive effect of spirapril and felodipine during repeated administration to spontaneously hypertensive rats.

The antihypertensive activity of spirapril given alone or in combination with felodipine was investigated in spontaneously hypertensive rats (SHR) during a 3-week treatment regimen and for one week after drug withdrawal. Systolic blood pressure and heart rate were recorded once a week just before dosing and at varying time intervals up to 6 hr thereafter. Recordings were continued for one week after drug withdrawal. Spirapril alone at 1 and 5 mg/kg p.o. was found to produce dose-related antihypertensive effects throughout the treatment period. Felodipine alone at 5 mg/kg p.o. reduced blood pressure slightly more than did the low dose of spirapril. The combination of spirapril and felodipine induced a marked antihypertensive response which was greater than that observed in rats treated with either drug alone. One week after treatment withdrawal, blood pressure was at initial levels with no evidence of rebound phenomena. No significant heart rate changes were observed in the treated groups, as compared with the controls, except for an increase on the 1st day of treatment in rats given felodipine. These findings indicate that the combination of an angiotensin converting enzyme (ACE) inhibitor with a calcium antagonist leads to an effective control of hypertension over a prolonged period of treatment. Since the combination allows effectiveness with lower doses of ACE inhibitor, it is expected that the antihypertensive efficacy might be associated with a lower liability to untoward effects.

Hemodynamic changes do not mediate the cardioprotection induced by the A1, adenosine receptor agonist CCPA in the rabbit.

Stimulation of adenosine A1 receptors is known to reduce infarct size in the rabbit heart. The aim of the present study was to verify whether a protective activity similar to that of the selective A1 receptor agonist, 2-chloro-N6-cyclopentyladenosine (CCPA), could also be obtained by inducing comparable hemodynamic effects with drugs having different mechanisms of action. The effects of the beta-adrenoceptor blocker atenolol, the calcium channel blocker felodipine, the A2A-selective adenosine receptor agonist 2-hexynyl-5'-N-ethyl-carboxamidoadenosine (2HE-NECA), and the non-selective adenosine receptor agonist 5'-N-ethyl-carboxamidoadenosine (NECA) were tested. Groups of 12-15 anesthetized open-chest rabbits received a 5-min infusion of CCPA (50 micrograms kg-1 min-1), atenolol (1 mg kg-1 min-1), felodipine (50 micrograms kg-1 min-1), 2HE-NECA (1 microgram kg-1 min-1), and NECA ( 1 microgram kg-1 min-1). Myocardial infarction was induced by a 30-min occlusion of a branch of the left coronary artery, followed by 3-h reperfusion. Infarct size was measured by tetrazolium staining. In controls, infarct size was about 40% of the zone at risk. Pretreatment with CCPA induced a marked decrease in heart rate (-40%) and blood pressure (-48%), and showed antiischemic activity (28% of the zone at risk). The other drugs tested produced similar effects on either heart rate (atenolol, -25%), or blood pressure (felodipine, 2HE-NECA and NECA, about -45%), but did not affect infarct size. IN this model, the reduction in infarct size by CCPA is most likely mediated by A1 receptors, since comparable hemodynamic effects, induced by other means, are not effective. A2A receptor stimulation does not appear to exert a protective effect.

Comparative ototoxicity of dibekacin and netilmicin in guinea pigs.

The cochleo- and vestibulotoxicity of dibekacin and netilmicin were compared in a guinea pig model. Both aminoglycosides were administered subcutaneously for 21 days at the dose level of 150 mg/kg/day. Control animals were injected with saline. Dibekacin-treated animals showed a significant (P less than 0.05) increase in the thresholds of the Preyer pinna reflex and the VIIIth nerve compound action potential in response to sound click stimulation. Moreover, a deterioration of the electrophysiologic auditory response and an almost complete suppression of the post-rotatory nystagmus were detected. In contrast, netilmicin did not induce any significant change in auditory and vestibular functions as compared to the control group. Our results demonstrated that netilmicin was devoid of ototoxicity in the guinea pig, while dibekacin provoked mild cochlear and severe vestibulotoxicity.

[Antiedema activity of a non-steroid physiological anti-inflammatory agent (author's transl)]. / Odemhemmende Aktivität einer steroidfreien, physiologischen, anti-inflammatorischen Substanz

The antiedema activity of experimental Lysoartrosi, a biological preparation, was demonstrated against edemas induced by carrageenin, formalin, dextran, serotonin, egg albumin and kaolin. Lysoartrosi, containing a mixture of polypeptides, is thus, the only preparation which is active against such a wide spectrum of inflammatory agents.