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PubMed1998

[Constrictive pericarditis illustrated by an unusual case report].

Constrictive pericarditis is an uncommon condition. Previously, tuberculosis or other bacterial infections were prevalent causes, often with prominent pericardial calcification. Presently, many patients with constrictive pericarditis of other aetiologies have lesser degrees of structural changes in the pericardium. We report on a case with severe symptoms where the correct diagnosis was elusive because of absent or minimal preoperative pericardial pathology. The clinical, echocardiographic and haemodynamic features of constrictive pericarditis are reviewed. We recommend thorough echocardiographic evaluation of central haemodynamics in patients with symptoms of heart failure when the aetiology is not readily apparent (e.g. previous myocardial infarction dilated cardiomyopathy or valvular disease.

Aged↗
PubMed2000

Increased alpha2-adrenergic constriction of isolated arterioles in diffuse scleroderma.

OBJECTIVE: Vasospasm and ischemic organ injury are important in the pathogenesis of systemic sclerosis (SSc; scleroderma). The present study was performed to determine whether SSc arterioles have an intrinsic disturbance in vasoconstrictor activity. METHODS: Skin biopsy samples were obtained from the upper arm of 11 patients with diffuse SSc (clinically uninvolved skin) and 8 age- and sex-matched control subjects. Dermal arterioles were dissected from the biopsy sample and mounted in a myograph for continuous monitoring of arteriolar diameter. The resting internal diameter of control and SSc arterioles was similar (mean +/- SEM 164+/-15 micro and 166+/-18micro, respectively). RESULTS: Dermal arterioles displayed no spontaneous constrictor activity in the absence of stimulation. Vasoconstriction in response to KCI, a receptor-independent activator of smooth muscle, or to phenylephrine, a selective alpha1-adrenergic receptor (alpha1-AR) agonist, was similar in control and SSc arterioles. However, constrictor responses to UK 14,304, a selective alpha2-AR agonist, were increased in SSc compared with control arterioles (maximal constriction responses of 25+/-5% and 67+/-4% [mean +/- SEM] in control and SSc arterioles, respectively; P = 0.000014). Mechanical denudation of the endothelium did not alter reactivity to alpha2-AR activation, indicating that the enhanced constriction in SSc was not mediated by changes in endothelial dilator activity. Indeed, in arterioles constricted with phenylephrine, the endothelial stimuli acetylcholine or bradykinin evoked endothelium-dependent relaxation that was similar in control and SSc arterioles. CONCLUSIONS: Vascular smooth muscle in SSc arterioles displayed a selective increase in alpha2-AR reactivity. The endothelial dilator function appeared normal. Altered activity of smooth muscle alpha2-ARs may contribute to the vasospastic activity that is a prominent feature of the SSc disease process.

Adrenergic alpha-2 Receptor Agonists↗
PubMed1994

Influence of various experimental parameters on the incidence of thermal and mechanical hyperalgesia induced by a constriction mononeuropathy of the sciatic nerve in lightly anesthetized rats.

In the current investigation we examined a peripheral mononeuropathy induced by four loose ligatures around the sciatic nerve. The nerve was treated with lidocaine or saline before implementing the ligatures (silk or chromic gut). The latency of the hindlimb withdrawal to noxious mechanical and radiant heat stimuli was tested under light pentobarbital anesthesia 3-10 days following the surgery. A latency/threshold difference > or = 15% between the hindlimbs was considered to represent a change in the nocifensive response. The adapting skin temperature of the hindlimbs was also measured. Pieces of hindpaw skin and the sciatic nerve were taken for histological evaluation. The results indicate that the incidence of hyperalgesia induced by a constriction mononeuropathy depended on the noxious submodality tested, and that the thermal and mechanical hyperalgesia were not coupled in all cases. Use of only one test modality led to false negative results. Furthermore, mononeuropathy-induced changes in the adapting skin temperature produced a considerable number of false positive results (an artefactual hyperalgesia) when radiant heat alone was used to determine the nocifensive withdrawal latency without paying attention to the abnormality of the skin temperature. A preemptive lidocaine treatment of the sciatic nerve before the nerve ligation significantly reduced the incidence of mononeuropathy-induced hyperalgesia. The nerve ligation material (silk vs chromic gut) was not a significant factor for the development of hyperalgesia induced by a constriction injury of a peripheral nerve. In histological evaluation the constriction injury-induced damage of the sciatic nerve was verified, and the inflammatory reaction caused by chromic gut was not stronger than that caused by silk ligatures. In general, immunohistochemical staining for substance P decreased whereas that for VIP increased. The results support the hypothesis that ligation-induced mechanical trauma and the afferent barrage induced by it, especially during the perioperative period, plays an important role in the development of postoperative hyperalgesia.

Adaptation, Physiological↗
PubMed1998

Dirofilaria immitis: heartworm infection converts histamine-induced constriction to endothelium-dependent relaxation in canine pulmonary artery.

Heartworm (Dirofilaria immitis) infection alters the behavior of vascular endothelial cells in vivo and in vitro, with the potential, therefore, to influence vascular function. Histamine, an autocoid implicated in the pathogenesis of parasitic and inflammatory diseases, is vasoactive, and causes endothelium-dependent relaxation in some vascular beds. Experiments were designed to determine if histamine is an endothelium-dependent vasodilator in in vitro rings of canine pulmonary artery from heartworm and control dogs; to elucidate the mechanisms involved in histamine vasoactivity; and to measure circulating levels of histamine. Dose-response relationships to histamine were done in rings of canine pulmonary artery from heartworm and control dogs, in the presence and absence of endothelial cells, the H1 receptor blocker tripelennamine, or the H2 receptor blocker cimetidine. Histamine caused a dose-dependent constriction in control, that was not influenced by endothelial cell removal. However, histamine caused an endothelium-dependent relaxation in heartworm pulmonary artery that was converted to constriction by endothelial cell removal. In heartworm, histamine relaxation was mediated by H2 receptors, but did not appear to involve nitric oxide or cyclooxygenase products. While diseases cause depression of endothelium-dependent relaxation, this is the first report of a disease that changes a constriction response to an endothelium-dependent relaxation.

Animals↗
PubMed1998

In vitro effect of DP-1904, a novel anti-asthma agent, against antigen-induced constriction and TXB2 release from the isolated guinea-pig lung parenchymal tissue.

The contractile activity and mobilisation of arachidonic acid metabolites in response to the antigen challenge were studied in isolated lung parenchymal tissue from the actively sensitised guinea pig. The sustained constriction of the lung tissue was evoked by the antigen, associated with significant liberation of TXB2, histamine and p-LTs. Other prostanoids (PGF2 alpha, PGD2, PGE2 and 6-keto-PGF1 alpha) were also released by the antigen challenge. DP-1904, an inhibitor of TX synthetase, significantly suppressed the late phase of the antigen-induced constriction. DP-1904 was potent to inhibit the production of TXB2, while DP-1904 accelerated the formation of PGF2 alpha, PGE2 and 6-keto-PGF1 alpha, presumably indicating the alternative changes of dilatory metabolites to the spasmogenic component. Mepyramine and FPL-77512 augmented the effect of DP-1904. AA-861 inhibited the antigen-induced constriction of the lung parenchymal tissue by inhibiting the release of p-LTs and TXB2. Pretreatment of the lung parenchymes with anti-guinea pig platelet serum, in order to deplete the platelets, did not affect the generation of TXB2 both in resting and also in the antigen-stimulated status, indicating that TXA2 is produced in the topical pulmonary tissue. It is concluded that DP-1904 inhibits the parenchymal contraction through potent inhibition of TXA2 generation, associated with significant elevation in PGE2 and PGI2.

Animals↗
PubMed1989

Methylxanthines augment the renin response to suprarenal-aortic constriction.

In a previous study we discovered that the adenosine receptor antagonist, caffeine, increases plasma renin activity and blood pressure in renin-dependent renovascular hypertension. The purpose of the present investigation was to determine whether methylxanthines augment the increase in renin secretion induced by a reduction in renal perfusion pressure and, if so, whether this effect is mediated by a direct action on juxtaglomerular cells. Accordingly, we examined the effects of infusions of caffeine and theophylline directly into the renal artery on the increase in renin secretion induced by suprarenal aortic constriction. All studies were conducted in dogs receiving an intravenous infusion of propranolol to prevent changes in renin secretion mediated indirectly via the sympathetic nervous system. Caffeine (5 mg/min) increased the renin response to suprarenal aortic constriction about 10-fold without significantly affecting renal hemodynamics or excretory function. Theophylline (5 mg/kg), on the other hand, did not significantly increase the renin response to a reduction in renal perfusion pressure, but did increase urine flow and sodium excretion about 10-fold. However, in the non-filtering, beta-adrenoceptor blocked, canine kidney, theophylline markedly increased the renin response to suprarenal aortic constriction. These results indicate that methylxanthines can potentiate the renin response to a reduction in renal perfusion pressure most likely by directly affecting the juxtaglomerular cells; however, since increased sodium delivery to the macula densa inhibits renin release, the extent to which methylxanthines affect the renin response to renal artery hypotension depends on how vigorous the diuretic response is to a given methylxanthine.

Adrenergic beta-Antagonists↗
PubMed1981

Partial inversion of the secondary constriction of chromosome 9. Does it exist?

Pericentric inversion of chromosome 9, a common abnormality, has been much studied because of its possible genetic effect. Apart from total inversion, in which the whole heterochromatic segment of chromosome 9 appears to be situated on the short arm, some authors describe partial inversion, in which the heterochromatin is found partly on the long arm and partly on the short arm. Our study indicates that firstly, the heterochromatic segment of chromosome 9 is composed of two biochemically different subunits: the heterochromatin of the centromere itself and the heterochromatin of the secondary constriction. Secondly, it suggests that partial inversion of the secondary constriction of chromosome 9 is an unusual event, as the majority of published cases can be interpreted as the result of an increase in the centromeric heterochromatin without alteration of the secondary constriction.

Centromere↗
PubMed1988

Detection of distinct structural domains within the primary constriction using autoantibodies.

We report the immunological differentiation of structures within the primary constriction. These include the kinetochore and the connecting strand, a structure which connects sister kinetochores. The location and temporal appearance of the connecting strand antigen suggest that it could play a role in the maintenance of sister chromatid pairing. In addition, we report the identification of a novel epitope that is localized to discrete patches along the entire length of the junction between sister chromatids at metaphase (the junction patch antigen). The patches on the inner surface of the euchromatic arms can be disrupted by Colcemid treatment while those found in the primary constriction remain intact. The apparent heterogeneity of the patches suggests that they may play different roles in the regulation of sister chromatid pairing. Because of their cytological localization and possible functional role, the junction patch and connecting strand antigens have provisionally been collectively termed CLiPs (Chromatid Linking Proteins). All of these antigenic sites are shown to be distinct from centromeric heterochromatin, which can itself be immunologically differentiated from the euchromatic arms. The relationship between the antigenicity of the primary constriction and the unique manner in which chromatin is organized in this region is discussed.

Animals↗
PubMed1995

Venules and arterioles in xenotransplanted human colon adenocarcinoma critically constrict with hyperthermia and serotonin.

Local and regional hyperthermia for treatment of cancer is often combined with radio- and chemotherapy. In this study we tested whether topically applied serotonin (5-HT) modulates tumor blood flow during local hyperthermia. The surgically unprepared ear microcirculation of anesthetized (75 mg/kg pentobarbital sodium) female nude athymic (nu/nu) mice (18-25 g) was used. Between 5 and 10 days after passaged pieces of human colon adenocarcinoma cells (1 microliter) had been implanted under the dorsal epidermis of the ear, that ear (tumor diameter 1.5 mm) was fixed on a temperature-regulated stage for measurement (via closed-circuit videomicroscopy) of the diameters of large and small (A1-3) arterioles and venules (V1-4), and capillaries, during local hyperthermia (28 degrees C-45 degrees C) and during local hyperthermia plus 1 mmol/l 5-HT. In the hyperthermia-alone group all skin vessels dilated, whereas all tumor vessels constricted with increasing temperatures. Hyperthermia combined with 5-HT caused dilation of skin arterioles, but skin venules constricted. In contrast, we observed constriction of all microvessels in human tumor xenografts with the combination of hyperthermia and 5-HT. We conclude that hyperthermia and 5-HT, applied intratumorally, could be clinically effective, since normal skin microcirculation is best protected with this treatment, while tumor blood flow is widely reduced.

Adenocarcinoma↗
PubMed1996

Factors in the cycle of violence: gender rigidity and emotional constriction.

A sample of 595 men were administered self-report assessments of childhood sexual and physical abuse, perpetration history, gender rigidity and emotional constriction. Including noncontact forms of sexual abuse, 11% of the men reported sexual abuse alone, 17% reported physical abuse alone, and 17% reported both sexual and physical abuse. Of the 257 men in the sample who reported some form of childhood abuse, 38% reported some form of perpetration themselves, either sexual or physical; of the 126 perpetrators, 70% reported having been abused in childhood. Thus, most perpetrators were abused, but most abused men did not perpetrate. Both sexually and physically abused men who perpetrated manifested significantly more gender rigidity and emotional constriction than abused nonperpetrators. Men who reported abuse but not perpetration demonstrated significantly less gender rigidity, less homophobia and less emotional constriction than nonabused men.

Adult↗
PubMed1991

Detection of the pupil constriction latency.

Two methods to accurately determine the moment of pupil constriction onset are discussed. For data sampled at a high rate (approximately 200 Hz) pupil velocity deviations from zero can simply be used, giving a satisfactory inaccuracy of about 5 ms. For data sampled at a low rate (less than 50 Hz), e.g. using a TV pupillometer, curve-fitting can be applied. It is demonstrated that curve-fitting, based on a second-order mathematical model, preceded by a linear trend, can result in an inaccuracy of less than 5 ms. Both methods give latencies independent of signal amplitude. This implies that a pupillometer yielding a relative measurement of the pupil area can be used for the detection of pupil constriction latencies. Furthermore it is demonstrated that the averaging of pupil constrictions results in an advanced moment of onset. Where latency differences of less than 25 ms are concerned, raw pupil data should therefore not be averaged.

Algorithms↗
PubMed1982

Norepinephrine constricts the canine coronary bed via postsynaptic alpha 2-adrenoceptors.

The effect of alpha 2-blockade (0.3 mg/kg i.v. rauwolscine) and alpha 1-blockade (1.2 mg/kg i.v. prazosin) on coronary constrictions induced by intracoronary injections of azepexole (B-HT 933, alpha 2-agonist, 0.1-10 microgram/kg), phenylephrine (0.3-3 microgram/kg) and norepinephrine (0.001-0.1 microgram/kg) were studied in dog hearts perfused in situ under beta-blockade. Constrictions by azepexole (antagonized by rauwolscine, yet resistant to prazosin and methysergide) demonstrated coronary alpha 2-adrenoceptors. Norepinephrine-induced constrictions were more attenuated (22-fold) by alpha 2-blockade than by alpha 1-blockade (2.6-fold) and thus were mediated mainly by activation of postsynaptic alpha 2-receptors.

Animals↗
PubMed1983

Effects of FPL-55712 or indomethacin on leukotriene-induced coronary constriction in the intact pig heart.

Intracoronary leukotriene D4, 0.1-3.0 micrograms (0.2-6.0 nmol), produced dose-dependent decreases in coronary flow of anesthetized pigs. Pretreatment with intracoronary FPL-55712 (0.1, 0.3 and 1.0 mg) reduced coronary constriction due to 1.0 micrograms leukotriene D4 by up to 77%. FPL-55712 did not produce sustained alterations in coronary flow, left ventricular end-diastolic pressure, systemic arterial pressure, or heart rate. Indomethacin pretreatment (6 mg/kg i.v.) had no effect on leukotriene-induced coronary constriction. Inhibition produced by FPL-55712 may be useful in disease states involving leukotriene-mediated coronary constriction.

Animals↗
PubMed1989

Endothelin-1 induces potent constriction of lymphatic vessels in situ.

The response of lymph vessels, arterioles and venules in the exteriorized rat mesentery to endothelin-1, vasopressin and norepinephrine was examined with the aid of high-resolution television microscopy. On a molar basis, endothelin-1 was more potent than vasopressin to contract the three types of vessels. Norepinephrine, which could constrict blood microvessels, did not act on lymph vessels. Acetylcholine, sodium-nitroprusside and isoproterenol were ineffective to block the constrictive responses of lymph vessels to endothelin-1 and vasopressin. At the same concentrations, however, acetylcholine and sodium-nitroprusside antagonized the responses of arterioles and venules to endothelin-1 and norepinephrine, whereas the responses of blood microvessels to vasopressin remained unaffected. Isoproterenol, at doses capable of blocking the response of the arterioles and venules to norepinephrine, did not interfere with the constriction induced by endothelin-1 and vasopressin on these vessels. It is suggested that endothelin-1 might play a role in the regulation of lymphatic contractility apart from its vasoconstrictor activity on blood vessels.

Animals↗
PubMed1992

The role of muscarinic M1 and M2 receptors in airway constriction in the cat.

The role of prejunctional inhibitory and facilitatory muscarinic receptors was investigated in cats with tracheal hyperresponsiveness to vagal stimulation. Intrathoracic airway caliber (total lung resistance (RL) and dynamic compliance (Cdyn] and the diameter of tracheal ring 4 were measured during vagal stimulation and local acetylcholine (ACh) injection before and after administration of the M1 receptor antagonist pirenzepine or the M2 receptor antagonist gallamine. The responses of tracheal ring 4, RL, and Cdyn to ACh were unaltered by gallamine or pirenzepine. Changes in RL and Cdyn during vagal stimulation were enhanced by gallamine, but the magnitude of tracheal constriction was unchanged. Vagally induced tracheal constriction was decreased by pirenzepine in hyperresponsive but not in control cats. The M2 receptors limit intrathoracic airway constriction, but a functional role for M2 receptors in the cervical trachea could not be demonstrated. However, these data suggest that M1 excitatory receptors may play a role in vagally mediated tracheal hyperreactivity.

Animals↗
PubMed1994

Modification by cyclopiazonic acid and ryanodine of depolarization-induced constriction in rat mesenteric artery.

Cyclopiazonic acid (53 or 159 nmol/min) or ryanodine (53 or 530 nmol/min) was applied to perfused rat mesenteric artery contracted with 40 mM K+ and 0.1 mM Ca2+. Both agents transiently elevated the perfusion pressure. The transient pressor response to caffeine observed after ryanodine was depressed more than after cyclopiazonic acid. This suggests that ryanodine increased the constriction through acceleration of Ca2+ release while cyclopiazonic acid increased it by inhibiting Ca2+ uptake into Ca2+ stores. In the continued presence of ryanodine, the next depolarization-dependent constriction was greatly depressed, suggesting that Ca(2+)-induced Ca2+ release was involved in the constriction.

Animals↗
PubMed1994

In vivo effect of naftidrofuryl on 5-hydroxytryptamine-mediated constriction in rat peripheral microcirculation.

Naftidrofuryl is commonly used in treatment of peripheral vascular disease. Its vasodilator action has been partly explained by its inhibitory effect of 5-HT2 receptors on peripheral arteries in vitro. The purpose of this study was to test in vivo whether naftidrofuryl selectively inhibits 5-hydroxytryptamine (5-HT)-mediated constriction of large arterioles in the peripheral microcirculation. This constriction appears to be 5-HT2 receptor-mediated. Three separate protocols were used to test the effects of naftidrofuryl: chronic injection (15 mg/kg, i.p., twice daily for 5-6 days; n = 7), acute intravenous (i.v.) infusion (15 mg/kg over 30 min; n = 7), or topical application (5 x 10(-8) M, n = 6; 5 x 10(-7) M, n = 5; 5 x 10(-6) M, n = 5; 10(-5) M, n = 7). Male Sprague-Dawley rats (145-185 g body weight) were anesthetized with sodium pentobarbital (50 mg/kg) and the cremaster muscle was prepared for intravital video microscopy. Diameter response of arterioles (70-120 microns) to increasing concentrations of locally applied 5-HT (10(-8)-10(-4) M) was assessed. In rats receiving no drug treatment, 5-HT caused vasoconstriction of arterioles beginning at 10(-6) M and reaching approximately 40% constriction at 10(-4) M. These vasoactive responses were not altered by chronic daily doses or an acute infusion of naftidrofuryl. 5-HT responses obtained with and without naftidrofuryl applied directly into the cremaster-bath also had little effect on the arteriole response at each of the four concentrations tested.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Origin of thromboxane-mediated constriction due to neuropeptides in canine basilar artery.

Bradykinin, substance P and vasopressin induced a vasodilatation followed by a vasoconstriction in control perfused canine basilar arteries with endothelium. The dilatation was significantly reduced and the constriction was significantly enhanced by endothelial removal with saponin. The potentiated constriction was significantly blocked by sodium ozagrel, a thromboxane synthetase inhibitor. These results suggest that the dilatation due to these neuropeptides may depend on endothelium-derived relaxing factor, and that the augmented constriction after endothelial removal may be related to the thromboxane A2 production in cerebral arterial smooth muscles. This mechanism following the damage of endothelium might be implicated in cerebral vasospasm after subarachnoid haemorrhage.

Adenosine Triphosphate↗