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Results for “Constriction, Pathologic”

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At least 19 recordsLinked to original sources
PubMed2003

Intrabolus pressure gradient identifies pathological constriction in the upper esophageal sphincter during flow.

Propulsion of a bolus through the upper esophageal sphincter (UES) is driven by a pressure drop in the direction of flow against frictional resisting force. Basic mechanics suggest that the axial rate of drop in intrabolus pressure (IBP), i.e., the intrabolus pressure gradient (IBPG), should be locally sensitive to abnormal constriction. We sought to quantify space-time patterns of IBP and IBPG that correlate with pathological disruption to transsphincteric bolus transport. High-resolution high-fidelity perfused manometry was applied concurrent with videofluoroscopy in 6 healthy controls and 10 patients with restricted UES opening and 4 bolus volumes. Pressures were interpolated spatially and displayed as space-time isocontours with bolus head and tail trajectories superimposed to identify the IBP domain. IBP and IBPG were averaged over an approximately steady period of transsphincteric flow. The axial location and magnitude of maximum IBPG were quantified for each swallow relative to the location of the abnormal restriction. We found that average hypopharyngeal IBP and locally maximal IBPG were significantly higher in the patient group (P < 0.001), whereas the maximum IBPG was insensitive to bolus volume, and the locations of maximum IBPG in the patient group were well correlated with axial locations of maximal UES constriction (r = 0.84, P < 0.01). Space-time structure of IBP and IBPG correlated qualitatively with swallow dysfunction. Because IBPG reflects pressure force driving the bolus against frictional force in the UES, IBPG reflects local changes in frictional resistance from pathological constriction during bolus flow. Consequently, the location and magnitude of IBPG reflect the existence and location of abnormal constriction, and IBP and IBPG structure reflect decompensation of the pharyngeal swallow.

Adult↗
PubMed2005

[Treating metastatic vertebral tumor with percutaneous vertebroplasty: a report of 28 cases].

BACKGROUND & OBJECTIVE: Treating metastatic vertebral tumor is a common difficulty. Conservative treatment can't efficiently release the pain, and establish the spinal column; while operation may destroy normal tissue, and cause many complications, which would prolong the time of in-hospital, and delay the treatment of primary disease, at the same time, operation is not suitable for multiple metastatic spinal tumors. This study was designed to investigate the efficacy of percutaneous vertebroplasty (PVP) on metastatic spinal tumor under the guidance of digital subtraction angiography (DSA). METHODS: A total of 58 patients with metastatic spinal tumor were divided into 2 groups according to their intention, 28 (group A) were treated with PVP combined radiochemotherapy, 30 (group B) were treated with routine radiochemotherapy. Baselines of the 2 groups have no significant difference. Two months after treatment, the life quality, therapeutic response, stabilization of the vertebral column, and toxic effect were compared between group A and group B. RESULTS: After treatment, both groups showed significant changes in life quality, and therapeutic response (P < 0.05, t(1)=2.74, t(2)=11.74). Group A showed no complication. Group B showed 5 cases of pathologic constrictive fracture in spinal body. CONCLUSION: PVP is a simple and minimally invasive treatment with few complications, which can release pain, decrease incidence of pathologic constrictive fracture in spinal body, and improve life quality of patients with metastatic spinal tumor.

Aged↗
PubMed2002

A morphometric model of lung mechanics for time-domain analysis of alveolar pressures during mechanical ventilation.

In this study we propose, and implement in the time domain, an anatomically consistent model of the respiratory system in critical care conditions that allows us to evaluate the impact of different ventilator strategies as well as of constrictive pathologies on the time course of acinar pressures and flows. We discuss the simplifications of the original Horsfield structure (Horsfield, K., et al. Models of the human bronchial tree. J. Appl. Physiol. 31:207-217, 1971), which were needed to enable the model implementation. The model has a binary tree structure including large airways represented as a combination of wall compliance and laminar resistance, small airways that have the same arrangement but can be heterogeneously constricted, and alveolar compartments that are viscoelastic second-order models to represent the stress adaptation behavior of lung tissue. We have described patient-ventilator interactions modeling the ventilator and the endotracheal tube. In conclusion this model makes it possible to investigate realistically the effect of homogeneous versus heterogeneous constrictive pathologies and the impact of different ventilatory patterns on pressure and flow distribution at the acinar level in the mechanically ventilated patient.

Bronchi↗
PubMed1992

An experimental painful peripheral neuropathy due to nerve constriction. I. Axonal pathology in the sciatic nerve.

A constriction injury to the sciatic nerve of the rat produces a painful peripheral neuropathy that is similar to the conditions seen in man. The pathology of the sciatic nerve in these animals was examined at 10 days postinjury, when the abnormal pain sensations are near maximal severity. The nerves were examined with (1) complete series of silver-stained longitudinal sections of pieces of the nerve (3 cm or more) that contained the constriction injury in the center, (2) toluidine blue-stained semithin sections taken at least 1 cm proximal and 1 cm distal to the constriction, and (3) EM sections taken adjacent to those stained with toluidine blue. One centimeter or more proximal to the constriction, both myelinated and unmyelinated axons were all normal. Nearer to the constriction, extensive degeneration of myelinated axons became increasingly common, as did signs of endoneurial edema. Distal to the constriction, the nerve was uniformly edematous and full of myelinic degeneration. There was a profound loss of large myelinated axons and a distinctly less severe loss of small myelinated and unmyelinated axons. These observations show that at 10 days postinjury the constriction produces a partial and differential deafferentation of the sciatic nerve's territory. The absence of degeneration in the nerve 1 cm proximal to the constriction indicates the survival of the primary afferent neurons whose axons are interrupted.

Animals↗
PubMed1992

Constrictive pericarditis in a mare: attempted treatment by partial pericardiectomy.

Chronic constrictive pericarditis was diagnosed in a 6-year-old Thoroughbred mare based on the clinical findings of right congestive heart failure, hyperechoic pericardium without pericardial effusion, and a dip-and-plateau shape of the right ventricular pressure curve with equilibration of the diastolic pressures in all cardiac chambers. Treatment was attempted by partial pericardiectomy using a right lateral thoracotomy approach. Because of severe epicardial involvement recurrence of the constrictive pathology was noted 6 weeks after the surgical procedure. However, in selected cases in which the disease process is limited to the pericardium, partial pericardiectomy may offer a mode of therapy in horses suffering from constrictive pericarditis.

Animals↗
PubMed2000

[Inhalative strategies for improvement of pulmonary hemodynamics and gas exchange in sepsis and severe pulmonary hypertension].

Chronic pulmonary hypertension and septic lung failure display different clinical features resulting in severe disturbances in the pulmonary circulation. In these diseases, the pulmonary bloodflow is impaired by a pathologic constriction of blood vessels that may lead to right ventricular overloading as well as serious worsening of gas exchange mainly caused by ventilation/perfusion mismatch. Various mechanisms deteriorating the vascular function may induce both an irreversible and a reversible contraction of pulmonary vessels, respectively. Two pharmacological approaches exist to reduce the vascular resistance: Reduction of the increased vascular tone by relaxation of vascular smooth muscle cells (effect of vasodilators). Inhibition of thrombus-mediated obliteration of the lung perfusion by use of anticoagulant and fibrinolytic drugs. Prevention of the structural reorganization of pulmonary vessels (vascular remodeling) by use of vasodilators with anti-inflammatory and anti-proliferative potency such as prostanoids. The systemic (intravenous or oral) application of vasodilative agents in sepsis and chronic pulmonary hypertension has, however, important side effects: Antagonism of the hypoxic pulmonary vasoconstriction aggravates the ventilation/perfusion mismatch (decrease in arterial oxygenation). Side effects of these vasodilators (systemic hypotension). The inhalative route of application is superior because of the pulmonary enrichment of the applied agent (pulmonary selectivity). Furthermore, a preferential deposition in the well-ventilated areas of the lung is achieved (intrapulmonary selectivity). Thus, the decrease in pulmonary-vascular resistance is paralleled by both optimized ventilation-perfusion matching and subsequently improved gas exchange. First clinical studies with inhaled nitric oxide and aerosolized prostacyclin have been performed in intubated and mechanically ventilated patients with septic lung failure. At present, the use of the long-acting prostacyclin analogue ilomedin for ambulant treatment of patients with chronic pulmonary hypertension is under investigation.

Acute Disease↗
PubMed2004

Receptor changes in cerebral arteries after subarachnoid haemorrhage.

Subarachnoid haemorrhage (SAH), occurring with a delay of 4-10 days is linked to cerebral vasospasm (CVS), a pathological constriction of the cerebral arteries. Several agents have been suggested as being responsible - amongst these perhaps 5-hydroxytryptamine (5-HT) and endothelin-1 (ET-1) are the most prominent, given their ability to elicit powerful constriction of arteries. Investigating both 5-HT and ET receptors we observed distinct changes in the receptor phenotype after experimental SAH - namely upregulation of the ETB and 5-HT1B receptors - linked to a higher sensitivity to the endogenous agonists. This multiple receptor upregulation may explain the failure in treating CVS using single receptor antagonists, and may also significantly change our understanding of the effector mechanism behind CVS. So far only the ET and 5-HT receptors have been studied in this regard, but other receptor systems may also undergo changes.

Animals↗
PubMed2005

Dopamine type 2 receptor expression and function in rodent sensory neurons projecting to the airways.

Agonists of the dopamine receptors have been demonstrated to have bronchodilatory properties in pathologically constricted airways. The mechanism by which these agonists induce bronchodilatation is thought to involve airway sensory nerves. In this study, the expression and function of dopamine D(2) receptor were examined in sensory ganglia supplying the airways. Neuronal dopamine D(2) receptor mRNA expression was demonstrated by single-cell RT-PCR following laser-assisted microdissection. The projection of the neurons to the airways was confirmed by retrograde neuronal labeling. In functional studies, dopamine D(2) receptor agonists (AR-C65116AB and ropinirole) inhibited intraneuronal calcium mobilization in rat capsaicin-sensitive primary sensory neurons and capsaicin-induced plasma extravasation in the rat trachea. Our results provide support to the hypothesis that dopamine D(2) receptor activation inhibits neurogenic inflammation and proinflammatory reflex responses.

Airway Obstruction↗
PubMed1998

Amniotic band syndrome: the association between rare facial clefts and limb ring constrictions.

The pathologic cause of both rare craniofacial clefts and congenital limb ring constrictions is the subject of some debate. Uncommon though these two conditions are, they have often been anecdotally reported in association. This study sought to determine the frequency of congenital limb anomalies in general and limb ring constrictions in particular amongst a population of patients with rare craniofacial clefts. Eighty-five cases of nonsyndromal, rare, craniofacial cleft were identified from a population of 280 patients assessed at the Women's and Children's Hospital, North Adelaide, with a diagnosis of rare craniofacial cleft classifiable by the Tessier system. Twenty-two patients (25.9 percent) displayed congenital limb anomalies. Eleven of these (12.9 percent) showed evidence of limb ring constrictions, a frequency much greater than in the general population. The group with limb ring constrictions demonstrated a significantly greater complexity of involvement with craniofacial clefting than the non-limb ring constriction group (4.27 clefts/patient versus 2.3 clefts/patient, p < 0.01). The distribution of craniofacial cleft locations in patients with evidence of limb ring constrictions was found to differ significantly from those with other or no limb anomalies (p < 0.01). The clefts in cases in which limb ring constrictions coexist are largely restricted to the paramedian 2-12, 3-11, 412 axes. This study confirms an association between rare craniofacial clefts and limb ring constrictions. The two conditions may therefore possess common etiology.

Abnormalities, Multiple↗
PubMed1990

Myocarditis and myocardial interstitial fibrosis in constrictive pericarditis--an extended pathological spectrum?

We performed endomyocardial biopsy in six patients with constrictive pericarditis, revealing the presence of myocarditis and myocardial interstitial fibrosis in all regardless of the endocardial thickening. These findings suggest that the presence of endomyocardial involvement in the setting of restrictive heart disease should not be deemed specific for endomyocardial fibrosis when the clinical evaluation suggests constrictive pericarditis.

Endomyocardial Fibrosis↗
PubMed2002

Complexities in ETS-domain transcription factor function and regulation: lessons from the TCF (ternary complex factor) subfamily. The Colworth Medal Lecture.

The ETS-domain transcription factor family can be divided into a series of subfamilies. Elk-1 represents the founding member of the ternary complex factor (TCF) subfamily. By focusing on the TCF subfamily, we can demonstrate the complexities that exist in the function and regulation of ETS-domain transcription factors. This article focuses on Elk-1 in detail and summarizes the functions of other TCFs. The key themes covered include the domain structure of the TCFs, the mechanisms of complex formation with serum response factor, regulation of TCFs by mitogen-activated protein kinase cascades, and transcriptional regulatory properties of the TCFs. Finally, the emerging role of the TCFs in vivo is discussed. A picture is developing indicating that, while these proteins exhibit significant sequence and functional conservation, key differences in their structure and regulation are being identified which may relate to unique functions of these proteins in vivo.

Amino Acid Sequence↗