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Biomedical subjects

J J Curtis

Publications and source records attributed to J J Curtis.

At least 19 recordsLinked to original sources
PubMed2001

Tolerance in renal transplantation after allogeneic bone marrow transplantation-6-year follow-up.

Despite significant advancements in clinical transplantation, very few reports describe the long-term acceptance of transplanted solid organs without indefinite immunosuppression. The immunosuppressive agents used are nonspecific and have serious potential side effects. We present a patient who received a living-donor renal allograft from the same person who had donated bone marrow to her several years earlier. Tolerance was expected based on previous acceptance of full-thickness skin grafts from the donor. Indeed, there has been no evidence of rejection during a 6-year follow-up period, and no induction or maintenance immunosuppression has been given. All noninvasive parameters of graft function remain normal. This and similar reports prove that genetically disparate solid organs can coexist without pharmacological immunosuppression.

Adult↗
PubMed2001

Mechanical circulatory support for acute heart failure.

Circulatory support devices are frequently required in postcardiotomy shock, postmyocardial infarction shock, and acute myocarditis. A panel of cardiac surgeons addressed the use of these devices in 4 patients. Cardiogenic shock after mitral valve replacement was considered best served by a left ventricular assist device (VAD) with apical rather than atrial cannulation. A left VAD should be placed first and a right VAD only if needed. Acute myocardial infarction shock was considered best treated with a left VAD with left ventricular cannulation to avoid thrombosis. If cardiac transplantation is an option, a long-term device must be considered. Young patients with acute fulminant myocarditis should be implanted with VADs in anticipation of recovery, and transplantation should be delayed. Patients with severe heart failure after coronary bypass grafting were considered best served by an extracorporal membrane oxygenation (ECMO) system or a VAD. Current postcardiotomy survival rates of postcardiotomy patients of 20% to 40% are worthwhile, but can be improved. Temporary devices such as ECMO can be changed to more long-term devices when necessary.

Acute Disease↗
PubMed2001

Tracheostomy: a risk factor for mediastinitis after cardiac operation.

BACKGROUND: We studied whether tracheostomy after coronary artery bypass grafting (CABG) is associated with higher incidence of mediastinitis and mortality, and whether shorter intervals between median sternotomy and tracheotomy are associated with higher incidence of mediastinitis. METHODS: Patients (n = 6,057) undergoing CABG since March 1977 were reviewed. Patients requiring tracheostomy and those developing mediastinitis were identified. Mediastinitis diagnosis required positive culture of mediastinal tissue or fluid. RESULTS: After CABG, 88 patients had tracheostomy performed (1.45%). Seven patients receiving tracheostomy after developing mediastinitis were excluded. Of the remaining 81 patients, 7 developed mediastinitis (8.6%) compared with 44 of 5,969 (0.7%) who did not require tracheostomy (p < 0.001). Mortality in tracheostomy patients was 24.7% (20 of 81) compared with 5.2% in patients not requiring tracheostomy (316 of 5,969; p < 0.001). Patients not developing mediastinitis had tracheostomy placement an average of 25 days after CABG compared with 18.7 days for those developing mediastinitis (p = 0.141). CONCLUSIONS: Tracheostomy after CABG is associated with increased incidence of mediastinitis and mortality. In this review, the time interval between CABG and tracheostomy was not predictive of mediastinitis. A larger sample size would be required to be confident that there is no correlation.

Aged↗
PubMed2001

Variables affecting weight gain in renal transplant recipients.

Previous studies of renal transplant recipients have suggested that weight gain after transplantation is relatively common, especially among certain populations. We conducted a retrospective review of 977 renal transplant recipients at the University of Alabama at Birmingham to identify patterns of weight change (as mean percentage of body weight at transplantation) attributed to race, sex, income, age at transplantation, pretransplantation time on dialysis, incidence of diabetes, rejection episode(s), and/or obesity (body mass index >/= 30 kg/m(2)) at transplantation. Patients were evaluated at 3, 6, 9, and 12 months posttransplantation and at 2 and 3 years, when available. Univariate analysis at 1 year showed that blacks achieved a greater weight change than whites (P = 0.0004), women had greater gains than men (P = 0.0001), and low-income patients had greater mean gains versus medium- (P = 0.0001) and high-income patients (P = 0.0001). Advancing age and weight gain were inversely correlated (P = 0.0002). Having one or more rejection episode indicated less weight gain than having no rejection episode (P = 0.0220). Incidence of diabetes or time on dialysis was not a significant predictor of weight gain. Black race, female sex, low income, younger age, and no incidence of rejection episodes were significantly associated with weight gain at 1 year in the multivariate analysis.

Adult↗
PubMed2000

The best way to manage hypertension after renal transplantation.

Hypertension in renal allograft recipients is a common problem arising from multiple factors, including peripheral vascular damage caused by pretransplant hypertension, side effects of immunosuppressive medications, allograft dysfunction, renal artery stenosis, recurrent glomerulonephritis, synthesis of vasoconstrictive hormones by the native kidneys, and excessive dietary salt intake. Identification of modifiable factors causing hypertension and concurrent medical conditions, and measurement of glomerular filtration rate, cyclosporine/tacrolimus blood levels, and magnitude of proteinuria are essential to tailor treatment for an individual patient. Lifestyles that exacerbate hypertension should be modified. For pharmacological therapy, diuretics and calcium channel blockers are first-line agents in patients on cyclosporine shortly after transplant. Angiotensin-converting enzyme inhibitors are good choices for patients with significant proteinuria. Reduction of immunosuppression will improve hypertension in some patients, but entails a potential risk of rejection or graft loss. Angioplasty is necessary in patients with a functionally significant stenosis of the allograft renal artery. Other patients on maximal medical therapy may benefit from native nephrectomy.

Humans↗
PubMed2000

Ross procedure for complex left ventricular outflow tract obstruction.

BACKGROUND: Complex left ventricular outflow tract (LVOT) obstruction in children continues to pose a significant therapeutic challenge to cardiac surgeons. The Ross procedure, in combination with resection of subaortic stenosis or a Konno type septal incision, is an important option for these difficult patients. METHODS: Recently two children aged 14 and 5 years with LVOT obstruction involving combined subaortic and valvar stenosis underwent surgical correction using the pulmonary autograft. Clinical presentation, operative technique, outcome and intermediate follow-up are detailed. RESULTS: One patient had resection of an isolated subaortic membrane in combination with a pulmonary autograft and the second a Ross Konno procedure. Postoperative hospital stays were without complication. Both patients were discharged at 5 days and have no significant obstruction nor semilunar valve insufficiency at 3 years' follow-up. CONCLUSIONS: Pulmonary autografts can be used in combination with resection of subaortic tissue or a septal incision for reconstruction of complex left ventricular outflow tract obstruction. This technique renders excellent short term valve function, relief of obstruction, avoids anticoagulation and provides potential for future growth.

Adolescent↗
PubMed1999

Minimally invasive lobectomy directed toward frail and high-risk patients: a case-control study.

BACKGROUND: To compare minimally invasive video-assisted thoracic surgery (VATS) with thoracotomy, cases were matched from a pool of pulmonary lobectomies performed by one surgeon who offered VATS for patients with unfavorable risk factors. METHODS: A thoracotomy case was paired to each of 19 VATS cases by age, sex, lobe, side, and forced expiratory volume in 1 second. Eleven VATS and 5 thoracotomy patients with severe activity impairments or reduced forced expiratory volume in 1 second (< 1.5 L or 50% predicted) were classified as higher risk than the others. RESULTS: Despite more high-risk cases, VATS yielded shorter hospitalizations (5.3+/-3.7 versus 12.2+/-11.1 days, p = 0.02), chest tube durations (4.0+/-2.8 versus 8.3+/-8.9 days, p = 0.06), and earlier returns to full preoperative activities (2.2+/-1.0 versus 3.6+/-1.0 months, p < 0.01). The VATS operations had no intraoperative complications and lasted 229+/-59 minutes. Pain 3 weeks later was dramatically better for the VATS group (none or mild, 63% versus 6%; severe, 6% versus 63%; p < 0.01). Six complications or deaths occurred in each group and were related to forced expiratory volume in 1 second, steroid usage, age, active smoking, and upper lobe resection (p < 0.01). Three VATS deaths occurred only in elderly, performance status 3 patients, with two caused by gastrointestinal-related problems masked by steroid use. CONCLUSIONS: A VATS lobectomy is less painful and may offer faster recovery for the frail or high-risk patient. Further study, particularly of its safety in severely activity-impaired patients, is warranted.

Aged↗
PubMed1999

Centrifugal pumps: description of devices and surgical techniques.

BACKGROUND: Because of simplicity of application, universal access, and low cost, centrifugal pumps are commonly used for short-term mechanical cardiac assist. Indications and techniques for application of this technology continue to evolve. METHODS: The clinical experience with 151 patients undergoing centrifugal mechanical cardiac assist at the University of Missouri-Columbia has been reviewed. We have compared commonly available centrifugal pumping systems in vitro and in vivo for characteristics that might distinguish them. RESULTS: Centrifugal pumps have been found to be well suited for use in surgery on the thoracic aorta, for extracorporeal membrane oxygenation and for postcardiotomy cardiac mechanical assist. Complications associated with centrifugal mechanical assist are predictable and common but potentially can be reduced by improved surgical techniques and anticoagulation strategies. In vitro and in vivo experimentation with available centrifugal pumps reveals nuances characteristic of each of the devices. CONCLUSIONS: All centrifugal pumps presently available are less destructive to blood cellular elements compared with roller pumps. With familiarity, all can function satisfactorily for short-term mechanical assist with no compelling evidence that favors any particular centrifugal pump system clinically available. Centrifugal pumps are ideally suited for left heart bypass during surgery on a thoracic aorta and for short-term application as may be required for postcardiotomy mechanical assist. Centrifugal pump technology should be part of the armamentarium of all cardiothoracic surgeons.

Animals↗
PubMed1999

Differences in bioavailability between oral cyclosporine formulations in maintenance renal transplant patients.

Previous studies of healthy volunteers and small numbers of transplant recipients have suggested that the oral solution formulation of Sandimmune (cyclosporine [CsA]; Sandoz Pharmaceuticals, East Hanover, NJ) is bioequivalent to the soft gelatin capsule (SGC) formulation. However, there is conflicting evidence as to whether the two formulations are bioequivalent in all patients; to date, there are no published studies that explicitly address their bioequivalence in patients. We conducted a randomized, open-label, two-sequence, two-period, crossover study. Of 20 maintenance renal transplant recipients shown by a screening pharmacokinetic (PK) profile to be poor absorbers of CsA, half were randomized to receive first the SGC formulation and half the oral solution formulation for a period of 7 days. Each patient then underwent a 12-hour PK profile on the last day of the assigned formulation before a crossover to receive the other formulation and repeat the 7-day treatment and PK profile cycle. The results showed that peak and total exposure to CsA was greater with the SGC formulation. The SGC-oral solution ratios indicated an average 38% greater peak and 11% greater total exposure for the SGC formulation (P < 0.01 and P = 0.09, respectively). Trough levels were more similar between formulations, with SGC showing an average of 5% greater troughs (P > 0.10). In our selected population of malabsorbers, the SGC formulation made a difference in drug exposure.

Administration, Oral↗
PubMed1998

Incidence and predictors of supraventricular dysrhythmias after pulmonary resection.

BACKGROUND: Patients undergoing pulmonary resection were evaluated prospectively in an effort to determine the incidence of and predictors for the development of postoperative supraventricular dysrhythmias. Specifically, we wished to test the hypothesis that the incidence of postoperative supraventricular dysrhythmias is dependent on the magnitude of pulmonary resection. METHODS: One hundred sixteen patients undergoing pulmonary resection had continuous Holter monitoring preoperatively, the day of operation, and the second postoperative day, as well as continuous cardiac monitoring throughout hospitalization. Holter interpretation was blinded to extent of resection. RESULTS: Twenty-six patients underwent pneumonectomy, 7 bilobectomy, 47 lobectomy, and 36 wedge resection. Twenty-six patients (22.4%) had supraventricular dysrhythmias, all atrial fibrillation +/- flutter. The incidence of atrial fibrillation with pneumonectomy, bilobectomy, single lobectomy, and wedge resection was 46.1%, 14.3%, 17.0%, and 13.8%, respectively (p < 0.005 pneumonectomy versus others). Overall, 31% of patients having pneumonectomy required pharmacologic therapy for dysrhythmia compared with 16% of patients having lesser resections, (p = 0.03). The peak incidence of onset of atrial fibrillation occurred on postoperative days 2 and 3 and lasted for less than 1 to 7 days, average 2.5 days. The average age of patients with dysrhythmias (64 years) was greater than those without (58 years) (p = 0.039). Thirty pre- and postoperative variables tested were not found to be significant predictors for development of postoperative atrial fibrillation. CONCLUSIONS: Atrial fibrillation occurs commonly after pulmonary resections but is not predictable. Development of atrial fibrillation is not dependent on the magnitude of pulmonary resection but is associated with the procedure pneumonectomy for reasons not elucidated.

Adult↗
PubMed1998

Effects of magnesium sulfate on electrical ventricular defibrillation of dogs.

Magnesium ion infusion has been reported for treatment of hypomagnesemia often associated with myocardial infarction and with surgeries involving cardiopulmonary bypass (CPB). Magnesium infusion before CPB has been reported to adversely affect the ability to defibrillate after CPB. However, there are also reports of magnesium ion infusion facilitating defibrillation of refractory ventricular fibrillation. This study evaluated the isolated effect of magnesium ion infusion on the shock intensity requirements for electrical defibrillation. The electric current required to defibrillate with 50% success (the ED50) was estimated in five mongrel dogs at baseline and again after each of four magnesium sulfate (80 mg/kg) infusions. The total serum magnesium level increased from 2.32 +/- 0.08 mg/dL (mean +/- SD) to 7.92 +/- 0.80 mg/dL. The mean estimated ED50 decreased from 12.8 +/- 2.9 A at baseline, to 11.1 +/- 0.8 A after the fourth infusion (P < .05), decreasing the delivered energy by 25%. Magnesium sulfate infusion was associated with a significant decrease in the electrical requirements for defibrillation. Key words: magnesium, electrical ventricular defibrillation.

Animals↗
PubMed1998

Living unrelated renal transplantation: progress and potential.

Transplant centers are turning to emotionally related or living unrelated kidney donors more often than in the past. Such donors are a benefit to the patient with end-stage renal disease, yet concern about their use persists. In the United States, the use of related donors has been well established in most centers. Nonetheless, there had been a reluctance to use nonrelatives that only recently has started to change. Most physicians agree that kidney transplant results are improved with living unrelated donor utilization. The transplant community needs to be watchful of the living unrelated donor operation. Both the welfare of the donor and the possibility of a "slippery slope" toward kidney bartering are considerations that need careful monitoring.

Evaluation Studies as Topic↗
PubMed1998

Losartan, an angiotensin II type 1 receptor antagonist, lowers hematocrit in posttransplant erythrocytosis.

The mechanism by which angiotensin-converting enzyme inhibitors reduce red cell mass in renal transplant recipients with erythrocytosis is unclear. To examine the role of angiotensin II in this disorder, losartan (a competitive antagonist of the angiotensin II type 1 [AT1] receptor) was administered to 23 patients with erythrocytosis. Fourteen patients took 25 mg/d for 8 wk; nine others were treated with 50 mg/d for 8 wk. Hematocrit decreased from 0.527 +/- 0.027 to 0.487 +/- 0.045 after 8 wk (P < 0.01)--by at least 0.04 in 19 patients. Decrement in hematocrit in the initial 8 wk of therapy was significantly greater in patients administered 50 mg/d than in patients on 25 mg/d. Twelve of 14 patients initially treated with 25 mg/d showed a small change in hematocrit; the dose was increased to 50 mg/d for 8 more wk. Hematocrit decreased from 0.528 +/- 0.030 before losartan treatment to 0.483 +/- 0.055 after 16 wk (P < 0.01). After therapy, serum erythropoietin significantly decreased in eight patients with elevated baseline levels, but not in 15 patients with normal baseline levels; however, hematocrit significantly decreased in both groups. Losartan was withdrawn in 16 patients; hematocrit increased from 0.440 +/- 0.057 to 0.495 +/- 0.049 after 8.9 +/- 7.5 wk (P < 0.001), without change in serum erythropoietin. Thus, specific blockade of AT1 receptors inhibited erythropoiesis, suggesting a pathogenic role for angiotensin II in posttransplant erythrocytosis.

Angiotensin Receptor Antagonists↗
PubMed1998

Neoral conversion from Sandimmune in maintenance renal transplant patients: an individualized approach.

When converting maintenance renal allograft recipients from Sandimmune (cyclosporin A [CsA]) to Neoral (CsA-microemulsion [CsA-ME]), a dose conversion ratio of 1:1 may not be optimal, in part because of the variability in absorption of the CsA formulation of cyclosporine. After conversion using a 1:1 dose ratio, an individualized approach to the management of dosing was applied. In this article, close monitoring, which began at the time of conversion, and rapid response to potentially meaningful changes in cyclosporine trough levels early in the postconversion course were used to maintain patients' cyclosporine troughs at preconversion levels. The results of cyclosporine dose changes after converting stable, maintenance renal transplant patients from CsA (once daily and twice daily) to CsA-ME (twice daily) during 52 wk of follow-up are reported. Most patients (87.2%) required CsA-ME dose reduction to maintain preconversion trough levels, and 64% of the patients attained their CsA-ME maintenance dose by study week 4. Logistic regression analysis identified one significant predictor concerning the week 52 CsA-ME dose: patients converted from CsA doses > or = 4.0 mg/kg per d were more likely to require dose reduction (P < 0.0001). Although firm guidelines for dose modification after conversion from CsA to CsA-ME cannot be provided because of the individual nature of cyclosporine absorption, an individualized approach to patient management is recommended. Patients with higher CsA doses before conversion are particularly likely to require dose reduction early in the postconversion course. With CsA-ME, good absorbers of cyclosporine remain good absorbers, or become better absorbers, whereas poor absorbers become good absorbers.

Adult↗