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PubMed1990

Rectovaginal constriction in Jersey cattle: genetics and breed dynamics.

Data from farmer-owned herds and from experimental matings supported monofactorial recessive inheritance of rectovaginal constriction in US Jersey cattle. Kempthorne's population genetics model of a recessive trait involving only male selection was extended to include mutation and converted to selection of females only. Computer analyses with that model estimate slow decline in the frequency of the gene for rectovaginal constriction. Practical dynamics of the disorder in a breed registering 50,000 females and 2,000 males annually are given for current conditions and after 500 generations of selection.

Alleles↗

PubMed1997

Attenuation of vasospasm and hemoglobin-induced constriction in the rabbit basilar artery by a novel protease inhibitor.

Calcium-activated proteolysis mediated by the protease inhibitor, calpain, has recently been implicated in the pathogenesis of cerebral vasospasm. The effect of one inhibitor of calcium-activated proteolysis, z-Leu-Phe-CONH-morpholene (zLF), on cerebrovascular constriction was examined in two experimental paradigms. In the first paradigm, the rabbit basilar artery (BA) was visualized via a transclival exposure, and its diameter was monitored using videomicroscopy. In the second experimental paradigm two intracisternal injections of autologous blood were administered to mimic a subarachnoid hemorrhage (SAH). The BA was visualized via the transclival exposure, and its luminal diameter was measured. Topical application of oxyhemoglobin (OxyHb), a known pathogenic agent in cerebral vasospasm, elicited vasoconstriction in normal animals, reducing arterial diameter to approximately 75% of resting levels. Pretreatment with zLF (100, 200, or 300 microM) attenuated vasoconstriction induced by OxyHb. In an experimental model of SAH, the diameter of the BA was reduced after the first injection of blood to approximately 67% of normal resting levels when measured 3 to 4 days later. This vasospastic response was reversed significantly by topical application of zLF (100 microM); vascular diameter was increased to approximately 84% of normal resting levels. These findings demonstrate that both acute OxyHb-induced constriction and blood-induced vasospasm are sensitive to an inhibitor of the proteolytic enzyme, calpain. Together, these observations indicate an important role for calcium-activated proteolysis in the development and maintenance of vasospasm after SAH. In addition, it may be inferred from the data that inhibitors of calcium-activated proteolysis may be useful therapeutic agents for treating this form of cerebrovascular disease.

Journal Article↗

PubMed1994

Effects of extravascular acidification and extravascular alkalinization on constriction and depolarization in rat cerebral arterioles in vitro.

The relationship between cell membrane potential, vessel diameter, and pH in small cerebral arterioles is not completely understood. This study involved direct, simultaneous measurement of cell membrane potential and vessel diameter at various extracellular pH levels. Arterioles ranging from 44 to 91 microns in diameter were isolated, transferred to a temperature-controlled microscope chamber, which was used as an organ bath, and observed through an inverted videomicroscope. Two vessel cannulation procedures were used: a single-sided cannulation with the other side occluded, and a double-sided and perfused cannulation. After cannulation, the vessels were pressurized to 60 mm Hg intraluminally and the bath temperature was raised to 37 degrees C. Cell membrane potentials of vessel wall cells were obtained after the bath temperature reached 37 degrees C with the vessels partly constricted and again after spontaneous tone (constriction) of the healthy vessels had developed. The effect of extraluminal pH on cell membrane potentials was studied by changing the bath pH from 7.3 to either 7.65 or 6.8 in the single-sided cannulation. The average cell membrane potential for vessels at 37 degrees C, with 60 mm Hg of intraluminal pressure and pH 7.3, was -37.5 mV. The cell membrane potential depolarized to -30.9 mV at pH 7.65 and hyperpolarized to -58.4 mV at pH 6.8, with a slope of 25.8 mV/pH unit. The effect of depolarizing extracellular potassium ions on the cell membrane potential was examined by perfusing two vessels with modified Ringer's solution containing 70 mM KCl. This perfusion method decreased the vessel diameter by 48% and depolarized the observed cell membrane potential from -41.9 to -19.8 mV, with a slope of -0.42 mV per percentage diameter change. These data provide the first measurements of membrane potentials of isolated penetrating arteriole wall cells in vitro. The results indicate that the cell membrane potential relates linearly to the vessel diameter. This new technique opens the possibility for studying vessel response to stimuli under controlled conditions and regulatory mechanisms such as the propagation of vasomotor responses.

Animals↗

PubMed1976

Effects of propranolol on renin release during chronic thoracic caval constriction or acute renal artery stenosis in dogs.

Dogs were given d,1-propranolol before and after thoracic inferior vena cava constriction (TIVCC) or renal artery constriction (RAC) to determine if the increase in plasma renin activity (PRA) and associated biological activity could be suppressed. Oral propranolol administration (240 mg twice daily) was begun at least 2 days prior to TIVCC in six dogs; heart rate was reduced from 133 to 95 beats/min but PRA did not change with propranolol administration. After TIVCC and during continued propranolol administration, daily renal sodium excretion fell from an average value of 50 to less than 3 mEq sodium/day and PRA was elevated two- to fourfold. With prolonged propranolol administration during TIVCC, PRA returned toward normal levels but renal sodium excretion remained low. At this time, hourly measurements of sodium excretion showed no change after a 240-mg oral dose or propranolol although very high plasma levels of propranolol were achieved; also, PRA was unchanged and low. The effects of RAC were studied before and during an intravenous propranolol infusion (0.2 mg/kg/hour) in conscious animals. Before propranolol administration, arterial pressure increased during RAC from 120 to 136 mm Hg and PRA doubled. Propranolol infusion lowered heart rate from 110 to 84 beats/min, but arterial pressure and PRA were not attentuated by propranolol during RAC. The data indicate that non-beta-adrenergic mechanisms are involved in renin release during TIVCC and RAC.

Animals↗

PubMed2001

A clinicopathologic study on three cases of constrictive bronchiolitis.

We describe the characteristic clinical and pathologic findings of three cases of constrictive bronchiolitis. All three patients were middle-aged women with chronic respiratory illness characterized by chronic cough, dyspnea, mild to severe obstructive pulmonary dysfunction, relatively normal chest radiographs with occasional peribronchial infiltration, and lack of response to bronchodilators or prednisolone. The patients also had medical diseases such as non-Hodgkin's lymphoma and hyperprolactinemia in case 1 and 3, respectively. None of the patients smoked cigarettes and had clinical evidence of recent viral lower respiratory tract infection. Histologic study by open lung biopsy revealed a spectrum of changes ranging from active cellular bronchiolitis to obliterative peribronchiolar fibrosis. The intervening interstitial and alveolar areas showed no remarkable lesion. Immunohistochemically, the bronchiolar or peribronchiolar inflammatory infiltrates mainly comprised of mixed T- and B-lymphocytes. It may be possible that the active form of constrictive bronchiolitis is initiated by attendant lymphocytic inflammation of the airways, which is followed by fibrous obliteration of bronchioles.

Adult↗

PubMed1995

Congenital constriction band syndrome.

There are many theories regarding the etiology of this rare syndrome. However, the current thinking is that these bands result from rupture of the amnion that causes permanent constrictions of extremities or amputations in utero. This clinically resembles temporary strangulation of an appendage by hair or thread, and must be distinguished. A historical overview as to the etiology of constriction bands will be presented, as well as case studies.

Adult↗

PubMedDate not supplied

[Spontaneous constriction of the fetal ductus arteriosus].

The case report describes the pre- and postnatal clinical and sonographic findings of a fetus with spontaneous constriction of Ductus arteriosus at 39 weeks gestation. An abnormal four-chamber view due to a hypertrophied and enlarged right ventricle, increased peak systolic (2.39 m/sec), increased peak diastolic (0.88 m/sec) velocities and the decreased pulsatility index of 0.92 were the diagnostic criteria. The flow of the right pulmonary artery was retrograde. After birth estimated pulmonary pressure was 50 mmHg. It is concluded that constriction of the fetal ductus arteriosus may also occur spontaneously in the absence of maternal drugs.

Adult↗

PubMed1999

Ag+ alters cell growth, neurite extension, cardiomyocyte beating, and fertilized egg constriction.

BACKGROUND: The Russian Space Agency uses electrochemically generated silver ions (Ag+) to purify drinking water for their space station, Mir, and their portion of the International Space Station. U.S. EPA guidelines allow 10.6 micromol x L(-1) Ag+ in human drinking water for up to 10 d. Studies correlate Ag+ exposure with tissue dysfunction in humans, rats, and mice, and with altered ion transport, skeletal muscle contraction, and embryonic cell constriction in other animal cells. Ag+ effects on cell shape change-related functions have not been assessed. METHODS: Immortalized embryonic human intestinal epithelial cells, freshly explanted embryonic avian nerve cells and cardiomyocytes, and marine fertilized eggs were grown in vitro in medium containing AgNO3. RESULTS: Intestinal cells detach from the substratum and viable cell number decreases by 5-6 d at 5 micromol x L(-1) AgNO3, and faster at higher concentrations. Microtubules appear unaltered in adherent cells. Detached cells are nonviable. Neurite outgrowth and glial cell migration from dorsal root ganglia are inhibited by 3 d at 15 micromol x L(-1) AgNO3 or greater. Contractions stop temporarily in most cardiomyocytes by 5 min at 5 micromol x L(-1) AgNO3 or more, but some cardiomyocytes beat 3 times faster than normal at 7.5-20 micromol x L(-1) AgNO3. Picomolar Ag+ increases marine egg polar lobe constriction within an hour, even in the absence of microtubules. CONCLUSION: Ag+ alters animal cell growth and shape changes by a MT-independent mechanism. This is the first report of Ag+ effects on vertebrate neurite outgrowth, glial cell migration, or cardiomyocyte beat rate.

Animals↗

PubMed2000

Constrictive pericarditis in a 19-month-old child.

We report a case of chronic nonspecific constrictive pericarditis with myocardial involvement in a 19-month-old infant. The patient underwent total pericardiectomy and had irreversible hemodynamic instability. Constrictive pericarditis is rare in childhood. It may follow several processes, most frequently an infectious disease. The natural course of the disease consists of progressive myocardial dysfunction with atrioventricular valvular involvement. When diagnosis is established early in the course of the disease and treatment started immediately, the evolution is favorable in most instances.

Journal Article↗

PubMed2000

Constrictive pericarditis in a 19-month-old child

Journal Article↗

PubMed2000

[Physiological role of respiratory-related bronchial constriction].

The respiration-related rhythmic constriction of the fifth-generation bronchi was analyzed in 11 tracheostomized dogs. During spontaneous breathing, the bronchial pressure (Pbr) estimated with a balloon-tipped catheter increased almost in parallel with the pleural pressure (Ppl) in the early inspiratory phase, but decreased in the late inspiratory phase. The parallel duration/inspiratory duration was 0.72 +/- 0.19 (mean +/- SD). This finding was more prominent in hypercapnia, but statistical significance was not obtained. When the efferent phrenic nerve fibers were electrically stimulated (pulse train, 0.1 ms, 30 Hz, 5 V, 2 s), Pbr changed almost in parallel with Ppl during the inspiratory phase, and expiration was completed significantly earlier than during spontaneous breathing (time constant 0.17 +/- 0.06 s vs 0.26 +/- 0.07 s). Bronchial constriction in early expiration may increase airway pressure and keep patency of the peripheral bronchi.

Airway Resistance↗

PubMed1975

Clinical and experimental studies of the congenital constriction band syndrome, with an emphasis on its etiology.

The findings in fifty-nine patients with congenital constriction band syndrome and in experiments in which limb malformations resembling those of the human constriction band syndrome were successfully reproduced in rat fetuses by amniocentesis indicated that these malformations arise from excessive contraction of the uterine muscle during pregnancy, with resulting hemorrhages from the marginal blood sinuses of the digital rays. Such malformations in humans may arise during the fifth and sixth weeks counted from ovulation. It therefore was concluded that this syndrome is not hereditary but is produced by prenatal environmental factors.

Amniocentesis↗

PubMed1975

[Constriction ring dystocia: a special form of uterine dystocia (author's transl)].

Constriction Ring Dystocia means a rare form of uterine dystocia (0.1%--1.7%). Pathophysiologically it means a hypertonic incoordinate anomaly of labor. The paper reports two cases of constriction ring, which had been recognized first during sectio cesarean. As the measure of choose is suggested to use tocolytica, although there do not exist any experiences and there was yet no chance to utilise these medicines because of lack of early recognition.

Adult↗

PubMedDate not supplied

Comparison of vasodilator effects on human middle cerebral artery constriction induced by vasoconstrictors or activated platelets.

Experiments were performed on de-endothelized perfused human middle cerebral artery constricted with noradrenaline, serotonin, prostaglandin F2 alpha and collagen-aggregated platelets, all of which provoked similar vasoconstriction; however, the ability of dipyridamole, prostacyclin and nifedipine to reduce the constriction was significantly less marked when induced by activated platelets. The decrease in drug antispasmatic effects was less marked for nifedipine than for other vasodilators. It was suggested that the resistance of platelet-induced vasoconstriction to vasodilator action depends on platelets ability to release several vasoactive substances simultaneously.

Adult↗

PubMed1992

Halothane relaxes previously constricted human epicardial coronary artery segments more than isoflurane.

To compare the vasodilatory effects of isoflurane versus halothane on coronary arteries in vitro, we studied the capacity of isoflurane and halothane to relax resting and previously constricted human coronary artery segments with use of in vitro tension recording. Human epicardial coronary artery segments (1.5-2.0 mm outside diameter) were obtained from hearts excised from recipient patients at time of heart transplantation. The effects of 0.5%, 1.0%, 2.0%, and 3.0% isoflurane or halothane on resting coronary artery segments stretched to their optimal resting tension were determined. Next, after removal of anesthetic from the bathing solution, the segments were constricted with K+ (60 mM), and this contraction was allowed to plateau. The arteries were then again exposed to isoflurane or halothane at 0.5%, 1.0%, 2.0%, and 3.0% concentrations. Isoflurane and halothane had no effect on noncontracted coronary artery segments stretched to their optimal resting tension. Halothane caused significant relaxation of K(+)-induced (60 mM) contractions at 2.0% and 3.0% but not at lower concentrations. Isoflurane did not cause significant relaxation of K(+)-induced (60 mM) contractions at any concentration studied. Our studies indicate that under the conditions studied, isoflurane at clinically relevant concentrations is not a significant coronary dilator.

Coronary Vessels↗

PubMed2005

Fillet flap: a successful procedure to preserve the optimum length of below-the knee-amputation stump in congenital constriction band of the leg.

The use of 'spare part' tissue from an amputated segment to cover a stump with soft tissue deficiency is a viable option for augmenting the shape of the stump and preserving functional length of the stump without additional donor morbidity. The procedure requires no microsurgical skill if the tissues are used as pedicle fillet flaps transfer. This concept of fillet flap makes the amputation distal to an unfavourable definitive amputation site such as in congenital constriction band possible. We report herein a case of amputation distal to constriction ring to illustrate the application of fillet flap in reconstruction surgery.

Adult↗

PubMed1991

Bronchodilating activity of broxaterol transdermal patch and its protective effect on bronchial constriction induced by inhaled distilled water mist.

The bronchodilating activity and the ability of broxaterol transdermal patch to inhibit bronchial constriction in response to distilled water mist (UNH2O) inhalation were assessed. The study was performed in 10 asthmatic patients in clinical remission according to a placebo-controlled, double-blind, randomized crossover design. Test medications were broxaterol patch (size = 1.75 cm2; programmed delivery = 105 mcg/h) and a matched placebo patch. A spirometric examination was performed before patch application (at 8:30-9:00 a.m.) and 24 hours later. Immediately afterwards, the UNH2O inhalation test was made, consisting of 3 bronchial exposures lasting 30, 60 and 120 s respectively with 3-minute intervals between challenges. Immediately after each exposure, a spirometric examination and specific airway resistance measurements were made. The results obtained show that broxaterol patch exerts a statistically significant bronchodilating effect and has a better protective effect than placebo patch on UNH2O-induced bronchial constriction. The local tolerability of patches was very good. Slight tremors were observed in some subjects.

Administration, Cutaneous↗

PubMed1991

[Hypertrophic arteriovenous fistula for hemodialysis. Reduction by means of a constrictive perivenous mesh].

Aneurysmal arteriovenous fistulae (AVF) for haemodialysis often need surgical closure. We present a technique which consists of inserting the AVF into a constrictive perivenous mesh tube, thereby bringing the caliber of the AVF down to its normal size and restoring the normal shape of the forearm. Nine patients underwent AVF constriction without postoperative events. All AVFs were patent at 4 months. This technique also has the advantage of saving veins which, of course, is worthwhile in patients under haemodialysis.

Arteriovenous Anastomosis↗