Search

SummaryD-dimer, a degradation product of fibrin, is being increasingly used as a marker and prognostic factor in various thrombotic diseases. Previous reports have shown that obstructive sleep apnea is associated with platelet activation and hypercoagulability. The aim of the study was to assess the potential role of the plasma D-dimer test in patients with obstructive sleep apnea. We designed a prospective group comparison study in a tertiary- care, university-affiliated medical center. One hundred and three patients of mean age 57 years (range 50–76 years) with symptoms suggestive of obstructive sleep apnea were included. Polysomnography was performed in all cases, and blood was collected for plasma D-dimer measurement by MiniQuant turbidmetric assay. The demographic and polysomnograph data were compared between patients with normal and high (>250 ng/ml) D-dimer levels. The group with higher D-dimer values had lower mean minimal oxygen saturation (72.1±16.4 vs. 81.7±11.6%, p=0.008) and a longer mean period of oxygen saturation below 90% (84.1±86.2 vs. 38.5±70.8 minutes, p=0.032). There was no correlation of respiratory disturbance index and sleep architecture with D-dimer values. We concluded that sleep apnea syndrome is associated with fibrinolytic activity. Oxygen desaturation seems to be one of the mediatory factors in the putative connection between obstructive sleep apnea and hypercoagulability state.

BACKGROUND AND OBJECTIVE: To determine the minimal oxygen delivery and pump flow that can maintain systemic oxygen uptake during normothermic (37 degrees C) pulsatile and non-pulsatile cardiopulmonary bypass in dogs. METHODS: Eighteen anaesthetized dogs were randomly assigned to receive either non-pulsatile (Group C; n = 9) or pulsatile bypass flow (Group P; n = 9). Oxygen delivery was reduced by a progressive decrease in pump flow, while arterial oxygen content was maintained constant. In each animal, critical oxygen delivery was determined from plots of oxygen uptake vs. oxygen delivery and from plots of blood lactate vs. oxygen delivery using a least sum of squares technique. Critical pump flow was determined from plots of lactate vs. pump flow. RESULTS: At the critical point, oxygen delivery obtained from oxygen uptake was 7.7 +/- 1.1 mL min(-1) kg(-1) in Group C and 6.8 +/- 1.8 mL min(-1) kg(-1) in Group P (n.s.). These values were similar to those obtained from lactate measurements (Group C: 7.8 +/- 1.6 mL min(-1) kg(-1); Group P: 7.6 +/- 2.0 mL min(-1) kg(-1)). Critical pump flows determined from lactate measurements were 55.6 +/- 13.8 mL min(-1) kg(-1) in Group C and 60.8 +/- 13.9 mL min(-1) kg(-1) in Group P (n.s.). CONCLUSIONS: Oxygen delivery values greater than 7-8 mL min(-1) kg(-1) were required to maintain oxygen uptake during normothermic cardiopulmonary bypass with either pulsatile or non-pulsatile blood flow. Elevation of blood lactate levels during bypass helps to identify inadequate tissue oxygen delivery related to insufficient pump flow

Lymphoproliferative disorder is a well-recognized complication of lung transplantation. Risk factors include Epstein-Barr virus infection and immuno-suppression. The gastrointestinal manifestations of posttransplant lymphoproliferative disorder in lung transplant recipients have not been fully characterized. Case presentation and 16 previously reported cases of posttransplant lymphoproliferative disorder with gastrointestinal involvement are reviewed. Patient ages ranged from 25 to 65 (median, 52) years. Median time from lung transplantation to onset of posttransplant lymphoproliferative disorder was 36 (range, 1–109) months; 35 percent of cases (6/17) occurred within 18 months; Eighty-eight percent of patients (15/17) had positive Epstein-Barr virus serology before transplantation. In five patients (29 percent), the posttransplant lymphoproliferative disorder also involved sites other than the gastrointestinal tract. The most common gastrointestinal site of posttransplant lymphoproliferative disorder was the colon, followed by the small intestine and stomach. Clinical features included abdominal pain, nausea, and bloody diarrhea. Diagnosis was based on typical pathologic changes on gastrointestinal tract biopsy obtained mainly by colonoscopy. Treatment included a reduction in the immunosuppressive regimen in 15 of 17 cases (88 percent) and surgical resection in 10 (59 percent). One patient was untreated. Seven of 16 patients (44 percent) responded to treatment and 9 patients died. Median time from onset of posttransplant lymphoproliferative disorder to death was 70 (range, 10–85) days. Posttransplant lymphoproliferative disorder with gastrointestinal involvement is a unique entity that should be considered in all Epstein-Barr-Virus-positive lung transplant recipients who present with abdominal symptoms. Although immunosuppressive modulation and resection can lead to remission, the risk of death is 50 percent.

ObjectiveSeveral studies have recently reported an association between aortic valve calcification and atherosclerosis of the cardiovascular system, suggesting that aortic valve calcification might represent an atherosclerosis-like process. Hence the aim of the present study was to determine whether there is a similar association between aortic stenosis and aortic atheromas.MethodsWe evaluated the records and echocardiographic videotapes of 91 consecutive patients with severe aortic stenosis who underwent intraoperative transesophageal echocardiography before aortic valve replacement to measure the presence and characteristics of aortic atheromas. There were 50 men (55%) and 41 women (45%). The mean age was 71.9 ± 9.4 years (range, 34–91 years). These patients were compared with 91 sex-and age-matched patients without aortic stenosis who underwent transesophageal echocardiography for various indications. Aortic atheroma was defined as localized intimal thickening of 3 mm or larger. A lesion was considered complex if there was a plaque extending 5 mm or more into the aortic lumen; if the lesion was protruding, mobile, or ulcerated; or both.ResultsThe aortic stenosis group had significantly higher rates of aortic atheromas (85% vs 37%, P < .001) and complex atheromas (47% vs 9%, P < .001) compared with the control group. In the vast majority of patients in the aortic stenosis group, the aortic atheromas were localized in the aortic arch (60 [66%] patients, with 50% being complex aortic atheromas) and in the descending aorta (70 [77%] patients, with 45.7% being complex aortic atheromas); in only 4 (4.4%) patients, the aortic atheromas were localized in the ascending aorta (50% complex aortic atheromas).ConclusionsThere is a strong association between the presence of severe aortic stenosis and the presence and severity of aortic atheromas, suggesting that aortic stenosis might be a manifestation of the atherosclerotic process. These findings imply that (1) aggressive atherosclerotic risk-factor modification for patients with aortic stenosis might be advisable and (2) consideration of evaluation of the aorta by means of transesophageal echocardiography before aortic valve replacement in selected patients might be helpful.

The minimum-time path for a robot arm has been a long-standing and unsolved problem of considerable interest. We present a general solution to this problem that involves joint-space tesselation, a dynamic time-scaling algorithm, and graph search. The solution incorporates full dynamics of movement and actuator constraints, and can be easily extended for joint limits and workspace obstacles, but is subject to the particular tesselation scheme used. The results presented show that, in general, the optimal paths are not straight lines, but rather curves in joint-space that utilize the dynamics of the arm and gravity to help in moving the arm faster to its destination. Implementation difficulties due to the tesselation and to combinatorial proliferation of paths are discussed.

Itraconazole is often given for fungal prophylaxis to lung transplant recipients after transplantation. The aim of this study was to determine the extent of interaction between tacrolimus and itraconazole in lung transplant recipients and the efficacy of itraconazole prophylaxis.The study group included 40 lung transplant recipients followed for at least 12 months. All received prophylactic itraconazole, 200 mg twice a day, for the first 6 months after transplantation. Tacrolimus levels and dosage requirements were compared during and after itraconazole therapy. Rejection rate, fungal infection rate, and renal function were assessed. The mean cost per daily treatment of the itraconazole/tacrolimus combination and tacrolimus alone was calculated.The mean tacrolimus dose during itraconazole treatment was 3.26 +/- 2.1 mg/day compared with 5.74 +/- 2.9 mg/day after itraconazole was stopped (p0.0001) for a mean total daily dose elevation of tacrolimus of 76%. When the cost of itraconazole was taken into account, the average total daily cost of the combined treatment was US5.86 dollars less than the treatment with tacrolimus alone. No differences in the rejection or fungal infection rate, or in renal toxicity, were observed between the periods with and without itraconazole treatment, although less positive fungal isolates were identified during itraconazole therapy.Prophylaxis therapy with itraconazole is highly effective. Itraconazole reduces the dose of tacrolimus and therefore lowers the cost of therapy without causing an increase in rejection rate and with renal function preservation.

OSTTRANSPLANT diabetes mellitus (PTDM) has gained widespread attention due to the micro- and macrovascular complications that increase the morbidity and mortality rates of patients receiving solid organs. A higher incidence of PTDM has been associated with immunosuppressive therapy. This study compares glucose metabolism in heart transplant recipients receiving either FK506 or cyclosporine. METHODS Two groups of heart transplant recipients, differing in their immunosuppressive regimen—FK506 or cyclosporin—were followed for periods up to 6 years. Blood levels of glucose and of the respective immunosuppressive agent were measured regularly, and, if needed, anti-hyperglycemic treatment prescribed. The concomitant therapy with low-dose steroids and azathioprine was the same for both cohorts. T-test were performed to compare with the mean values of the two groups. RESULTS

T IS NOW well recognized that the gap between the supply of available transplantable human organs and the need is constantly increasing. Medical suitability is the basis of organ allocation, although the social, economic, psychologic, and demographic situation of each potential recipient represents important considerations. The ethical dilemma that we face is whether foreign, nonresident candidates should be placed on a national waiting list, and, if the answer is positive, under what terms? Organ transplantation, especially heart or lung, requires not only a well-trained group, but also an extensive infrastructure, which does not exist in each country. The lack of organs in the one hand and the lack of infrastructure in other countries on the other hand lead to the need for a mutual partnership among nations. Among the 100 organs transplanted in our center, 3 were donated by nonresident Palestinians who were treated in Israeli hospitals, 1 of whom was a victim of a violent act during the “Intifada.” The Palestinian population, although being provided with diverse medical services, is not entitled to be on the Israeli national waiting list. The ethical question that the medical community faces in these circumstances is whether to accept a family request to donate the organs to a close relative of the donor instead of offering them to all patients on the list. The other debate is whether the waiting list should be equally open to residents and nonresidents, now that they have became part of the potential population to donate.

HEART and liver transplantation have become the treatment of choice in end-stage heart or liver failure. Advances in surgical technique and the introduction of cyclosporine A have improved survival following transplantation, but allograft rejection is still common and remains a major cause of morbidity and late graft failure. Transplantation results in the recipient’s immune activation, however, because of baseline immunosuppressive therapy only some recipients manifest clinical symptoms of rejection. Induction immunosuppression after heart and liver transplantation has mainly been based on regimens previously used in renal transplantation. Modern regimens use triple-drug treatment: cyclosporine or FK 506, prednisone, and azathioprine for almost all organ recipients without questioning basic differences in immunoactivation. Beta-2-microglobulin (B2m) is a low molecular weight protein associated with HLA class I antigens and is of value for immunologic monitoring. B2m has been shown to significantly increase after heart, liver, or renal transplantation without clinical evidence for rejection. The purpose of this study was to explore differences in immunoactivation between stable heart and liver transplanted patients to improve long-term monitoring and immunosuppressive therapy.

THE NUMBER of patients awaiting organ transplantation has progressively increased over the last decade. The progression of the discrepancy between suitable donors and potential recipients on waiting lists will have the consequence of an increasing use of organs from marginal donors. Organs that would have been thought unsuitable for transplantation not so long ago are currently used for transplantation. Advanced age, prolonged CPR, heavy inotropic support, or coronary lesions define marginal donors. Marginal recipients are advanced in age, have other diseases as limiting factors, or have been hospitalized in critical condition. From a total number of 100 transplantations (heart and/or lung) performed in our center, we present three cases in which ethical difficulties arose.

TYPE THE WORDS “kidney transplantation” or “heart transplantation” or a similar combination into one of the more robust search engines on the World Wide Web and you will retrieve hundreds of thousands of different sites that refer to the specialty in some manner. Most international and national transplant associations have web sites, and a world of news, research, clinical cases, and statistical data are available on-line over the Internet. The aim of this study was to search international and national transplantation databases

THE OBJECTIVE of all scientific publications regardless of their type or size, is the international exchange of knowledge and new ideas. The United States, Germany, United Kingdom, Japan, and European countries are the leading contributors to medical science. In particular, the contribution of individual countries may depend on factors such as the language spoken and the population size. Organ transplantation in Israel is a therapeutic modality for end-stage organ diseases. The number of transplantations has increased since 1963. In the present study, we evaluated the contributions of Israel and of other nations in the field of organ transplantation according to their population size.

ATRIAL fibrillation (AF) is the most common dysrhythmia seen early after major thoracic surgery. Atrial dysrhythmia has been observed in children undergoing lung transplantation, but AF after adult lung transplantation in the early postoperative period has not previously been reported. A Heart and Lung Transplantation Unit in the Department of Cardiothoracic Surgery in a university hospital is the setting for this retrospective analysis.

The minimum-time path for a robot arm has been a long standing and unsolved problem of considerable interest. We present a general solution to this problem which involves joint-space tessellation, a dynamic time-scaling algorithm, and a graph search. The solution incorporates full dynamics of movement and actuator constraints, and can easily be extended for joint limits and workspace obstacles. It was found that optimal paths tend to be nearly straight lines in joint space. We discuss implementation difficulties due to the tessellation and to combinatorial proliferation of paths.

An efficient algorithm is presented for the calculation of the inverse kinematic accelerations for a six-degree-of-freedom manipulator with a spherical wrist. The inverse kinematic calculation is shown to work synergistically with the inverse dynamic calculation, producing kinematic parameters needed in the recursive Newton-Euler dynamics formulation. Additional savings in the dynamic computation are noted for a class of kinematically well-structured manipulators, such as spherical-wrist arms, and for manipulators with simply structured inertial parameters.

Superificial thrombosis is among the most frequent complications of varicose veins. Miscellaneous treatments have been attempted for relief of patients' symptoms, most of them unsatisfactory. We advocate simple evacuation of the thrombosed varix followed by elastic bandaging and walking exercises, a regimen which gives relief in a short period. Treatment of varicose veins should follow; no drug therapy is necessary.