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P Moore

Publications and source records attributed to P Moore.

At least 73 records · Page 4Linked to original sources
PubMed2000

Coronary to pulmonary artery collaterals in patients with pulmonary atresia and ventricular septal defect.

BACKGROUND: The frequency, distribution, and surgical importance of coronary artery to pulmonary artery (CAPA) collaterals have not been established. The aim of this study was to establish prevalence, anatomical pattern, and significance of CAPA in patients with pulmonary atresia and ventricular septal defect (PA/VSD). METHODS: We reviewed cardiac catheterization and operative data of 87 consecutive, unselected patients who underwent one-stage complete unifocalization for PA/VSD and assessed major systemic to pulmonary collaterals from July 1992 to June 1998. RESULTS: CAPA collaterals were diagnosed in 9 of 87 patients (10%). The collaterals originated from the left coronary artery system in 7 patients and the right in 2. Collaterals from the left coronary system arose from the left main coronary artery in 3 patients and the circumflex in 4. All collaterals joined the central pulmonary artery, which bifurcated and supplied both lungs. One collateral from the right coronary system joined the stump of the main pulmonary artery and the other gave origin to a true left pulmonary artery, which was the sole supply to 75% of the left lung. Coronary artery enlargement was seen in 2 patients only. No patient had evidence of myocardial ischemia. Coronary collaterals comprised a dual source of pulmonary blood flow in all but 1 patient. During unifocalization, the CAPA collaterals were ligated at its origin in all cases, and the collateral from the right coronary to the left pulmonary artery was unifocalized. CONCLUSIONS: The prevalence of CAPA collaterals in patients with PA/VSD is approximately 10%. The diagnosis may be missed without appropriate angiograms. We recommend selective ascending aortogram or selective coronary angiogram in all patients.

Adolescent↗
PubMed2000

Surgical intervention for complications of transcatheter dilation procedures in congenital heart disease.

BACKGROUND: Transcatheter interventions have assumed an important role in the management of many forms of congenital heart disease. While complications of transcatheter interventions are uncommon and usually minor, significant complications requiring operation do occur on occasion. The purpose of this report is to present our experiences with seven such complications, and to review the literature on this topic. METHODS: Seven patients who required operation after a transcatheter dilation procedure between 1992 and 1998 are described. Three patients required retrieval of retained foreign bodies (stents or balloons), and repair of the underlying abnormality. Two patients underwent repair of fistulas between 2 great vessels, or a great vessel and a cardiac chamber. One patient required operation for a postdilation aneurysm. One patient underwent urgent repair of severe aortic regurgitation after balloon aortic valvuloplasty. RESULTS: All patients survived and are doing well, with no further need for catheter or operative intervention, from 8 months to 6 years after operation. Additional reported complications requiring operation are discussed as well. CONCLUSIONS: Operation for complications of catheter interventions in congenital heart disease is seldom necessary. Though uncommon, a variety of such complications may occur, including vascular, valvar, intracardiac, and foreign body complications. When operation is required, results are typically very good.

Cardiac Catheterization↗
PubMed2000

Incidence and implications of systemic to pulmonary collaterals after bidirectional cavopulmonary anastomosis.

BACKGROUND: Systemic to pulmonary arterial collaterals often develop after bidirectional cavopulmonary anastomosis (BCPA). It has been proposed that such collaterals may be related to perioperative outcome and duration of effusions after the modified Fontan procedure. However, the incidence and significance of collaterals after BCPA remain uncertain. METHODS: To evaluate risk factors for, and significance of, such collaterals, we reviewed angiographic and clinical data for all 76 patients who underwent BCPA between January 1990 and June 1996 and had follow-up catheterization during or before 1997. RESULTS: The median age at BCPA was 10 months, and the median duration from BCPA to follow-up catheterization was 18 months. Arterial collaterals were detected on follow-up catheterization in 45 patients (59%). Factors associated with collateral development included a prior right-sided systemic-to-pulmonary arterial shunt, lower pre-BCPA end-diastolic ventricular pressure and pulmonary vascular resistance, and use and duration of cardiopulmonary bypass during the BCPA operation. Fourteen of the 45 patients (30%) underwent coil embolization of the collaterals. Forty-three patients have undergone extracardiac conduit Fontan, with 1 early and 1 late death. Collaterals were present in 22 of these patients, 7 of whom underwent pre-Fontan embolization. The duration from BCPA to Fontan was longer in patients with collaterals, but these patients were not more likely to have prolonged effusions than those without, and the duration of tube thoracostomy was significantly shorter in patients with collaterals. Embolization of collaterals did not affect the duration of effusions. CONCLUSIONS: Systemic-to-pulmonary arterial collaterals are common after BCPA. In contrast to prior reports, collaterals were not associated with a higher incidence of prolonged effusions after the Fontan procedure in our experience, and did not correlate with poor outcome.

Collateral Circulation↗
PubMed2000

A numerically efficient model for simulation of defibrillation in an active bidomain sheet of myocardium.

Presented here is an efficient algorithm for solving the bidomain equations describing myocardial tissue with active membrane kinetics. An analysis of the accuracy shows advantages of this numerical technique over other simple and therefore popular approaches. The modular structure of the algorithm provides the critical flexibility needed in simulation studies: fiber orientation and membrane kinetics can be easily modified. The computational tool described here is designed specifically to simulate cardiac defibrillation, i. e., to allow modeling of strong electric shocks applied to the myocardium extracellularly. Accordingly, the algorithm presented also incorporates modifications of the membrane model to handle the high transmembrane voltages created in the immediate vicinity of the defibrillation electrodes.

Algorithms↗
PubMed2000

Pulmonary blood flow alters nitric oxide production in patients undergoing device closure of atrial septal defects.

OBJECTIVE: To determine the effect of pulmonary blood flow (Qp) on nitric oxide (NO) production in patients with increased Qp due to an atrial septal defect (ASD). BACKGROUND: Alterations in pulmonary vascular NO production have been implicated in the development of pulmonary hypertension secondary to increased Qp. In vitro, acute changes in flow or shear stress alter NO production. However, the effect of Qp on lung NO production in vivo is unclear. METHODS: Nineteen patients (2.4-61 years of age, median 17) with secundum ASD undergoing device closure were studied. Before, and 30 min after ASD closure, exhaled NO and plasma nitrate concentration were measured by chemiluminescence (NOA 280, Sievers, Boulder, Colorado). RESULTS: Before ASD closure, all patients had increased Qp (Qp: systemic blood flow [Qs] of 2.0 +/- 0.7) and normal mean pulmonary arterial pressure (13.4 +/- 3.1 mm Hg). Atrial septal defect device closure decreased Qp from 6.0 +/- 2.5 to 3.6 +/- 1.3 L/min/m2 (p < 0.05). Mean pulmonary arterial pressure was unchanged. Associated with the decrease in Qp, both exhaled NO (-22.1%, p < 0.05) and plasma nitrate concentrations (-17.9%, p < 0.05) decreased. CONCLUSIONS: These data represent the first demonstration that acute changes in Qp alter pulmonary NO production in vivo in humans. Exhaled NO determinations may provide a noninvasive assessment of pulmonary vascular NO production in patients with congenital heart disease. Potential correlations between exhaled NO, pulmonary vascular reactivity and pulmonary hypertension warrant further study.

Adolescent↗
PubMed2000

Clinical and physiological consequences of rapid tryptophan depletion.

We review here the rapid tryptophan depletion (RTD) methodology and its controversial association with depressive relapse. RTD has been used over the past decade to deplete serotonin (5-hydroxy-tryptamine, or 5-HT) in humans and to probe the role of the central serotonin system in a variety of psychiatric conditions. Its current popularity was stimulated by reports that RTD reversed the antidepressant effects of selective serotonin reuptake inhibitors (SSRIs) and monoamine oxidase inhibitors (MAOIs) in remitted patients with a history of depression but not in patients treated with antidepressants which promote catecholaminergic rather than serotonergic neurotransmission (such as tricyclic antidepressants or buproprion). However, RTD has inconsistent effects in terms of full clinical relapse in depressed patients. Pooling the data from all published reports, patients who are either unmedicated and/or fully remitted are much less likely to experience relapse (7 of 61, or approximately 9%) than patients who are recently medicated and partially remitted (63 of 133, or approximately 47%; although, the numbers here may reflect patient overlap between reports). Recently remitted patients who have been treated with non-pharmacological therapies such as total sleep deprivation, electroconvulsive therapy, or bright light therapy also do not commonly show full clinical relapse with RTD. We briefly review RTD effects in other psychiatric disorders, many of which are treated with SSRIs. There is accumulating evidence to suggest that RTD affects central serotonergic neurotransmission. Nevertheless, many questions remain about the ability of RTD to reverse the beneficial effects of SSRIs or MAOIs, or to induce symptoms in unmedicated symptomatic or asymptomatic patients.

Antidepressive Agents↗
PubMed2000

Evaluation of the morphology of the oval fossa for placement of devices.

OBJECTIVES: First, to examine the morphology of heart specimens with defects of the oval fossa so as to define the factors that facilitate appropriate selection of the size of devices used for inteventional closure. Second, to examine the relationship between morphology and transthoracic and transesophageal echocardiography. BACKGROUND: The success of transcatheter closure is influenced by the variable morphology of deficiencies with the oval fossa, and of the relationship of the fossa itself to adjacent structures. More appropriate selection could reduce the incidence of failures. METHODS: From over 100 specimens in the cardiac registry at the University of California, San Francisco, we judged 16 hearts with atrial septal defects within the oval fossa, either in isolation or associated with other cardiac malformation, to be suitable for this study. We measured the dimensions of the defect and the surrounding rims of the fossa. All values were normalized to the diameter of the aortic root. RESULTS: A fenestrated defect was present in 9 specimens (56%). The shape defect itself was oval in all specimens, with a ratio of major to minor axes of 1.70 + 0.63. The major axis took one of three main directions with respect to the vertical plane: in 11 specimens (69%o) it was at horizontal; in 3 (19%) it was at oblique at an angle of 45 degrees; and in 2 (12%) it was vertical. Discordance was noted in some hearts between the major axis of the defect and that of the oval fossa. Structures closest to the rim of the fossa were the aortic mound, the coronary sinus, and the hinge point of the aortic leaflet of the mitral valve. CONCLUSIONS: Extrapolating from these specimens permitted identification of the major and minor axes of the atrial septal defect by transthoracic and transesophageal echocardiography. Our study has identified landmarks and dimensions that may be employed to improve effectiveness of selection of patients for transcatheter closure of defects within the oval fossa.

Cadaver↗
PubMed2000

Transesophageal echocardiographic predictors for successful transcatheter closure of defects within the oval fossa using the CardioSEAL septal occlusion device.

OBJECTIVES: To define the utility of transesophageal echocardiography in predicting the likelihood of a successful procedure and residual shunting in patients undergoing transcatheter closure of defects within the oval fossa using the CardioSEAL device. BACKGROUND: Transesophageal echocardiography is used to monitor transcatheter closure of interatrial defects within the the oval fossa, but predictors of successful closure and residual shunting have yet to be determined. METHODS: We reviewed transesophageal echocardiograms obtained from 26 consecutive patients undergoing attempted transcatheter closure of interatrial defects within the oval fossa between January, 1997 and May, 1998. Assessment of the atrial septum, the septal defect, and the rims of the oval fossa bordering the defect was performed in 3 planes: longitudinal, 4-chamber, and basal short-axis. RESULTS: Closure proved successful in 24 patients (92%). The defect was significantly larger, and the anterosuperior rim of the defect smaller, in the 2 patients in whom occlusion was not successful. Residual shunting 24 hrs after closure was detected in 14 patients. Significant predictors of leakage included smaller posterior and superior rims, a larger shunt prior to closure, and herniation of a one left atrial arm of the device into the right atrium. In all cases, the sites of leakage were the superior rim of the defect at the superior cavo-atrial junction, and the anterosuperior rim behind the aortic root. Herniation of a left atrial arm into the right atrium was seen in 7 patients (29%). In all, it was the anterosuperior arm which herniated Doppler color flow was suboptimal in detecting residual leaks, and was enhanced substantially with the use of contrast echocardiography. CONCLUSIONS: Transesophageal echocardiography allows excellent assessment of the oval fossa and deficiencies of its floor in all of their dimensions. It is an important tool for guiding the deployment of the occlusion device in patients undergoing attempted transcatheter closure of defects within the fossa. Contrast echocardiography should be used for optimal detection of residual shunting.

Adolescent↗
PubMed2000

Coronary arterial size late after the atrial inversion procedure for transposition of the great arteries: implications for the arterial switch operation.

BACKGROUND: Coronary flow reserve in the hypertrophied ventricle is reduced. One contributing factor may be the size of the proximal coronary arteries. In patients who undergo atrial inversion procedures for transposition of the great arteries, the left coronary artery supplies the pulmonary ventricle and may be smaller than the right coronary artery. We hypothesized that the dimensions of the coronary arteries may correlate with symptomatic status after atrial inversion and may be an important factor when these patients are considered for the arterial switch operation. METHODS: The proximal left and right coronary arteries were measured in 9 patients with transposition and failure of the systemic right ventricle after atrial inversion, 10 asymptomatic patients after atrial inversion, and 10 patients with normal hearts. The diameters of the coronary arteries were indexed to body surface area and compared. RESULTS: The absolute and indexed diameters of the right coronary artery were greater in symptomatic patients than in asymptomatic patients (indexed: 3.1 +/- 0.6 vs 2.4 +/- 0.4 mm/m(2), P <.001) or control patients (2.0 +/- 0.3, P <.001), and the absolute diameter of the left coronary artery was smaller (2.9 +/- 0. 7 vs 3.6 +/- 0.5 mm, P =.003 [asymptomatic], 3.6 +/- 0.5 mm, P =.01 [control]). In symptomatic patients, the absolute and indexed diameters of the left coronary artery were smaller than those of the right (indexed: 2.1 +/- 0.6 vs 3.1 +/- 0.6 mm/m(2), P <.001). By contrast, there was no difference in asymptomatic patients (2.2 +/- 0.5 vs 2.4 +/- 0.4 mm/m(2), P =.44), and the left coronary artery was larger in normal control patients (2.2 +/- 0.4 vs 2.0 +/- 0.3 mm/m(2), P <.001). CONCLUSIONS: Differences in the sizes of the proximal coronary arteries may be related to symptomatic status in patients with transposition of the great arteries who have undergone an atrial inversion procedure, as well as to the efficacy of ventricular retraining. When pulmonary artery banding and subsequent arterial switch are considered for patients with a Mustard or Senning procedure and a failing systemic right ventricle, the size of the proximal coronary arteries may be an important factor and should be evaluated with preoperative imaging studies.

Adult↗
PubMed2000

Mice harboring a defective epidermal growth factor receptor (waved-2) have an increased susceptibility to acute dextran sulfate-induced colitis.

BACKGROUND: It has been reported that epithelial growth factor (EGF) and transforming growth factor-alpha (TGF-alpha) play an important role in colonic mucosal defense and repair. Waved-2 (wa-2) mice harboring a defect EGF-R and phenotypically similar to TGF-alpha knockout mice provide a novel approach to study the role of EGF-R ligands in the maintenance and repair of colonic mucosa. METHODS: Acute colonic mucosal injury was induced by oral administration of dextran sodium sulfate (DSS: 5 g%) given for 6 days ad libitum to wa-2 homozygotes and their genetic controls (n = 10, each group), as well as to wa-2 mice with and without exogenous EGF administration. Severity of colonic injury was assessed histologically of the entire colon and graded. A crypt damage score (CDS) reflecting all three grades of mucosal pathology was calculated. Decrease in total body weight, colon length and colonic blood content was determined for all groups. RESULTS: Thirty-eight percent of the entire colonic mucosa was destroyed in wa-2 animals compared to 15% in control mice. The CDS was 16.0 +/- 1.4 and 9.6 +/- 0.8 in wa-2 and control mice, respectively. EGF application to wa-2 mice did not reduce the severity of mucosal injury (CDS: 18.9 +/- 1.7 and 19.4 +/- 2.1 in EGF and vehicle injected mice, respectively). CONCLUSIONS: The increased susceptibility of wa-2 mice to DSS demonstrates the pivotal role of EGF-R ligands such as EGF and TGF-alpha in preserving the integrity of the colonic mucosa against mucosal injury. The missing beneficial effect of exogenous EGF administration in these mice further underlines the importance of an intact ligand/EGF-R pathway.

Animals↗
PubMed2000

Coculture of bladder urothelial and smooth muscle cells on small intestinal submucosa: potential applications for tissue engineering technology.

PURPOSE: Small intestinal submucosa is a xenogenic, acellular, collagen rich membrane with inherent growth factors that has previously been shown to promote in vivo bladder regeneration. We evaluate in vitro use of small intestinal submucosa to support the individual and combined growth of bladder urothelial cells and smooth muscle cells for potential use in tissue engineering techniques, and in vitro study of the cellular mechanisms involved in bladder regeneration. MATERIALS AND METHODS: Primary cultures of human bladder urothelial cells and smooth muscle cells were established using standard enzymatic digestion or explant techniques. Cultured cells were then seeded on small intestinal submucosa at a density of 1 x 105 cells per cm.2, incubated and harvested at 3, 7, 14 and 28 days. The 5 separate culture methods evaluated were urothelial cells seeded alone on the mucosal surface of small intestinal submucosa, smooth muscle cells seeded alone on the mucosal surface, layered coculture of smooth muscle cells seeded on the mucosal surface followed by urothelial cells 1 hour later, sandwich coculture of smooth muscle cells seeded on the serosal surface followed by seeding of urothelial cells on the mucosal surface 24 hours later, and mixed coculture of urothelial cells and smooth muscle cells mixed and seeded together on the mucosal surface. Following harvesting at the designated time points small intestinal submucosa cell constructs were formalin fixed and processed for routine histology including Masson trichrome staining. Specific cell growth characteristics were studied with particular attention to cell morphology, cell proliferation and layering, cell sorting, presence of a pseudostratified urothelium and matrix penetrance. To aid in the identification of smooth muscle cells and urothelial cells in the coculture groups, immunohistochemical analysis was performed with antibodies to alpha-smooth muscle actin and cytokeratins AE1/AE3. RESULTS: Progressive 3-dimensional growth of urothelial cells and smooth muscle cells occurred in vitro on small intestinal submucosa. When seeded alone urothelial cells and smooth muscle cells grew in several layers with minimal to no matrix penetration. In contrast, layered, mixed and sandwich coculture methods demonstrated significant enhancement of smooth muscle cell penetration of the membrane. The layered and sandwich coculture techniques resulted in organized cell sorting, formation of a well-defined pseudostratified urothelium and multilayered smooth muscle cells with enhanced matrix penetration. With the mixed coculture technique there was no evidence of cell sorting although matrix penetrance by the smooth muscle cells was evident. Immunohistochemical studies demonstrated that urothelial cells and smooth muscle cells maintain the expression of the phenotypic markers of differentiation alpha-smooth muscle actin and cytokeratins AE1/AE3. CONCLUSIONS: Small intestinal submucosa supports the 3-dimensional growth of human bladder cells in vitro. Successful combined growth of bladder cells on small intestinal submucosa with different seeding techniques has important future clinical implications with respect to tissue engineering technology. The results of our study demonstrate that there are important smooth muscle cell-epithelial cell interactions involved in determining the type of in vitro cell growth that occurs on small intestinal submucosa. Small intestinal submucosa is a valuable tool for in vitro study of the cell-cell and cell-matrix interactions that are involved in regeneration and various disease processes of the bladder.

Child↗
PubMed2000

Success and failure of the defibrillation shock: insights from a simulation study.

INTRODUCTION: This simulation study presents a further inquiry into the mechanisms by which a strong electric shock fails to halt life-threatening cardiac arrhythmias. METHODS AND RESULTS: The research uses a model of the defibrillation process that represents a sheet of myocardium as a bidomain. The tissue consists of nonuniformly curved fibers in which spiral wave reentry is initiated. Monophasic defibrillation shocks are delivered via two line electrodes that occupy opposite tissue boundaries. In some simulation experiments, the polarity of the shock is reversed. Electrical activity in the sheet is compared for failed and successful shocks under controlled conditions. The maps of transmembrane potential and activation times calculated during and after the shock demonstrate that weak shocks fail to terminate the reentrant activity via two major mechanisms. As compared with strong shocks, weak shocks result in (1) smaller extension of refractoriness in the areas depolarized by the shock, and (2) slower or incomplete activation of the excitable gap created by deexcitation of the negatively polarized areas. In its turn, mechanism 2 is associated with one or more of the following events: (a) lack of some break excitations, (b) latency in the occurrence of the break excitations, and (c) slower propagation through deexcited areas. Reversal of shock polarity results in a change of the extent of the regions of deexcitation, and thus, in a change in defibrillation threshold. CONCLUSION: The results of this study indicate the paramount importance of shock-induced deexcitation in both defibrillation and postshock arrhythmogenesis.

Electric Countershock↗
PubMed2000

A comparison of hydrofibre and alginate dressings on open acute surgical wounds.

This study aimed to compare the performance of a hydrofibre (Aquacel) and an alginate (Sorbsan) dressing on acute surgical wounds left to heal by secondary intention. A total of 100 patients were prospectively randomised pre-operatively to receive either the hydrofibre or the alginate dressing. Dressing performance was measured at operation, at 24 hours and seven days. Parameters measured included ease of: application and removal of the first dressing; re-application on the first postoperative day; and removal and re-application one week postoperatively. The hydrofibre dressing received higher scores for all of these categories. Patients in this group also experienced less pain (mild or none) on removal of the first dressing and at one week. However, these results did not achieve statistical significance, and should be seen as a trend. Nevertheless, the authors recommend the use of hydrofibre dressings on open acute surgical wounds.

Acute Disease↗
PubMed1999

Early T cell response in the central nervous system in canine distemper virus infection.

The initial demyelinating lesions in canine distemper virus (CDV) infection develop during a period of severe immunosuppression in the absence of inflammation. In vitro and in vivo studies suggest that early demyelination is due to directly virus-induced oligodendroglial changes. In the present spatiotemporal study in experimentally CDV-infected dogs we observed diffuse up-regulation of T cells throughout the central nervous system (CNS) and T cell invasion in early demyelinating lesions. Invasion of T cells in the CNS occurred despite severe immunosuppression and without any perivascular cuffing. However, the major fraction of invading T cells correlated with sites of viral replication and coincided with the demonstration of an early immune response against the nucleocapsid protein of CDV. Activation of microglial cells was thought to have elicited the migration of T cells to the CNS by secretion of chemokines: marked IL-8 activity was found in the CSF of dogs with acute lesions. In areas of early demyelination, large numbers of CD3+ cells accumulated in the tissue in the absence of any morphological sign of inflammation. Whether the T cells at lesion sites contribute to the development of acute demyelination remains uncertain at this stage. Antiviral cytotoxicity was not apparent since viral clearance in demyelinating lesions is only effective when B cells and concurring antiviral antibody production appeared in the subacute and chronic inflammatory stage of the disease. CD3+ cells appear to persist for several weeks after infection since they were also found in recovered dogs that did not develop demyelination. Accumulation of immune cells, including a significant proportion of resting T cells (CD45RA+) in the CNS in the early stages of the disease may facilitate the later development of the intrathecal immune response and associated immunopathological complications.

Animals↗