Thermosensitive paramagnetic liposomes for temperature control during MR imaging-guided hyperthermia: in vitro feasibility studies

RATIONALE AND OBJECTIVES: Magnetic resonance (MR) imaging-based temperature monitoring has gained interest for use in general hyperthermia treatment of tumors. Such therapy requires an accurate control of the temperature, which should range from 41 degrees to 45 degrees C. A novel type of thermosensitive MR agent is proposed: liposome-encapsulated gadolinium chelates whose temperature response is linked to the phase-transition properties of the liposome carrier. In vitro relaxometry and MR imaging were used to evaluate the thermosensitivity of the contrast properties of liposomal gadolinium diethylenetriaminepentaacetic acid bis(methylamide) (Gd-DTPA-BMA). MATERIALS AND METHODS: T1 relaxivity (rl) measurements of liposomal Gd-DTPA-BMA were undertaken at 0.47 T and at temperatures of 20 degrees-48 degrees C. MR imaging was performed at 2.0 T with a gel phantom containing inserts of liposomes. Diffusion-weighted and T1-weighted gradient-recalled echo images were acquired as the phantom was heated from 22 degrees to about 65 degrees C. RESULTS: At ambient temperature, the r1 of liposomal Gd-DTPA-BMA was exchange limited due to slow water exchange between the liposome interior and exterior. A sharp, marked increase in r1 occurred as the temperature reached and exceeded the gel-to-liquid crystalline phase-transition temperature (Tm) of the liposomes (42 degrees C). The relaxation enhancement was mainly attributable to the marked increase in transmembrane water permeability, yielding fast exchange conditions. There was good correlation between the relaxometric and imaging results; the signal intensity on T1-weighted gradient-recalled echo images increased markedly as the temperature approached Tm. The temperature sensitivity of the diffusion-weighted technique differed from that of the liposome-based T1-weighted approach, with an apparent water diffusion coefficient increasing linearly with temperature. CONCLUSION: Since the transition from low to high signal intensity occurred in the temperature range of 38 degrees - 42 degrees C, the investigated paramagnetic liposomes have a potential role as "off-on" switches for temperature control during hyperthermia treatment.     

Tranexamic acid in total hip arthroplasty saves blood and money: a randomized, double-blind study in 100 patients

BACKGROUND: A blood transfusion is a costly transplantation of tissue that may endanger the health for the recipient. Blood transfusions are common after total hip arthroplasty. The total saving potential is substantial if the blood loss could be reduced. Studies on the use of tranexamic acid have shown interesting results, but its benefits in total hip arthroplasty have not yet been resolved. PATIENTS AND METHODS: 100 patients receiving a total hip arthroplasty (THA) got a single injection of tranexamic acid (15 mg/kg) or placebo intravenously before the start of the operation. The study was double-blind and randomized. Total blood loss was calculated from the hemoglobin (Hb) balance. Volume and Hb concentration of the drainage was measured 24 h after the operation. Intraoperative blood loss was estimated volumetrically and visually. RESULTS: The patients who received tranexamic acid (TA) bled less. The total blood loss was on average 0.97 L in the TA group and 1.3 L in the placebo group (p < 0.001). 8/47 (0.2) in the TA group were given blood transfusion versus 23/53 (0.4) in the placebo group (p = 0.009). Drainage volume and drainage Hb concentration were less in the TA group (p < 0.001 and p = 0.001). No thromboembolic complications occurred. INTERPRETATION: Considering the cost of blood and tranexamic acid only, use of the drug would save EUR 47 Euro per patient. We recommend a preoperative single dose of tranexamic acid for standard use in THA.     

Cemented tibial component fixation performs better than cementless fixation: a randomized radiostereometric study comparing porous-coated, hydroxyapatite-coated and cemented tibial components over 5 years

Background The question whether the tibial component of a total knee arthroplasty should be fixed to bone with or without bone cement has not yet been definitely answered. We studied movements between the tibial component and bone by radiostereometry (RSA) in total knee replacement (TKR) for 3 different types of fixation: cemented fixation (C-F), uncemented porous fixation (UC-F) and uncemented porous hydroxyapatite fixation (UCHA-F).

Patients 116 patients with osteoarthrosis, who had 146 TKRs, were included in 2 randomized series. The first series included 86 unilateral TKRs stratified into 1 of the 3 types of fixation. The second series included 30 patients who had simultaneous bilateral TKR surgery, and who were stratified into 3 subgroups of pairwise comparisons of the 3 types of fixation.

Results After 5 years 2 knees had been revised, neither of which were due to loosening. 1 UCHA-F knee in the unilateral series showed a large and continuous migration and a poor clinical result, and is a pending failure. The C-F knees rotated and migrated less than UC-F and UCHA-F knees over 5 years. UCHA-F migrated less than UC-F after 1 year.

Interpretation Cementing of the tibial component offers more stable bone-implant contact for 5 years compared to uncemented fixation. When using uncemented components, however, there is evidence that augmenting a porous surface with hydroxyapatite may mean less motion between implant and bone after the initial postoperative year.     

Safety, Complications, and Satisfaction of Patients Undergoing Submuscular Breast Augmentation via the Inframammary and Endoscopic Transaxillary Approach

Background Since its introduction, augmentation mammaplasty has gained widespread popularity, as demonstrated by the fact that an estimated 2 million women in the United States have received implants. During recent decades, several surgical approaches have evolved in terms of implant placement or site of access to the surgical plane. Debate has existed concerning the questionable superiority of a particular technique for achievement of optimal results. Thus, the inframammary approach, an established and widely accepted technique for breast augmentation, and endoscopically assisted transaxillary breast augmentation were retrospectively compared in terms of safety and aesthetic outcome, as measured, respectively, by the rate of postoperative complications and patient satisfaction. Methods This study analyzed 78 patients undergoing augmentation mammaplasty between 1997 and 2004. Only patients seeking primary augmentation mammaplasty solely for aesthetic reasons were included in the study. Previously performed breast surgery and simultaneously conducted ipsilateral mastopexy were among the exclusion criteria. Patient satisfaction was assessed using the client satisfaction questionnaire (CSQ-8) because of its easy applicability. Results The complication rate was low in both patient subsets, thus confirming the safety of the transaxillary approach, as compared with the more common submammary technique. However, a higher level of satisfaction was detected in the former patient group, indicating a more favorable aesthetic outcome with the transaxillary augmentation mammaplasty. Conclusion Endoscopically assisted transaxillary augmentation mammaplasty is a safe method with predictable results associated with a high level of patient satisfaction. If applied in the setting of appropriate indications, it is an excellent tool for use with patients who prefer to have an incision at a distant site.     

Prevalence of co-morbidity in different European RRT populations and its effect on access to renal transplantation.

BACKGROUND: This study compared the prevalence of co-morbidity in patients starting renal replacement therapy (RRT) between European countries and further examined how co-morbidity affects access to transplantation. METHODS: In this ERA-EDTA registry special study, 17907 patients from Austria, Catalonia (Spain), Lombardy (Italy), Norway, and the UK (England/Wales) were included (1994-2001). Co-morbidity was recorded at the start of RRT. RESULTS: The prevalence of co-morbidity was: diabetes mellitus (DM) (primary renal disease and co-morbidity) 28%, ischaemic heart disease (IHD) 23%, peripheral vascular disease (PVD) 24%, cerebrovascular disease (CVD) 14% and malignancy 11%. With exception of malignancy, the prevalence of co-morbidity was highest in Austria, but differences were small among other countries. With exception of DM, males suffered more often from co-morbidity than females. In general, the percentage of haemodialysis was higher in patients with co-morbidity, but treatment modality differed substantially between countries. Using a Cox regression with adjustment for demographics, country, year of start and other co-morbidities, the presence of each of the co-morbid conditions made it less likely [RR; 95%CI] to receive a transplant within 4 years: DM [0.79; 0.70-0.88], IHD [0.59; 0.50-0.70], PVD [0.57; 0.49-0.67], CVD [0.49; 0.39-0.61], and malignancy [0.32; 0.24-0.42]. The age, gender and year of start adjusted relative risk [95%CI] to receive a renal transplant within 4 years ranged from 0.23 [0.19-0.27] for Lombardy (Italy) to 3.86 [3.36-4.45] for Norway (Austria = reference). These international differences existed for patients with and without co-morbidity. CONCLUSIONS: The prevalence of co-morbidity was highest in Austria but differences were small among other countries. The access to a renal graft was most affected by the presence of malignancy and least affected by the presence of DM. International differences in access to transplantation were only partly due to co-morbid variability.     

Survival with pain: An eight‐year follow‐up of war‐wounded refugees

The aim of this study was to investigate the nature of chronic pain in male war‐wounded refugees and to examine the relationship between chronic pain and psychiatric symptoms. A culturally heterogeneous group of 44 war‐wounded refugees were investigated during hospitalization, shortly after arrival, and followed up after two years. This study is an additional follow‐up after eight years. The data collection methods used were structured interviews and physical examination. The measures of outcome were: Visual Analogue Scale (VAS) grading of pain; clinical categorization of pain into nociceptive or neurogenic; Hopkins Symptom Check List (HSCL‐25); Post Traumatic Symptom Scale (PTSS‐10). Chronic pain was found in 32 (73%) out of 44 subjects. The pain was purely nociceptive and neurogenic in 53% and 25%, respectively. The frequency of psychiatric symptoms was significantly related to the mean intensity of pain. War‐wounded refugees display psychiatric symptoms and chronic pain in a complex pattern. Further research is needed as a basis for pain rehabilitation programmes suitable for this group.     

Systemic and cavernous plasma levels of vasopressin in healthy males during different functional conditions of the penis

The role of the sympathetic adrenergic system in mediating the constant tone of penile flaccidity and returning the erect penis to its flaccid state is fairly well established. However, it is not yet known whether additional nonadrenergic-noncholinergic transmitters are involved in this process. Arginine-vasopressin (AVP, ADH), a pituitary peptide hormone with potent vasoconstrictor activity, may be one of the factors contributing to such control. The present study was undertaken to determine whether or not plasma levels of AVP change during penile flaccidity, tumescence, rigidity, and detumescence. We determined the plasma levels of AVP in the systemic as well as the cavernous blood of 25 healthy adult male volunteers who were exposed to visual and tactile erotic stimuli in order to elicit penile tumescence and erection. Whole blood was aspirated from the corpus cavernosum and the cubital vein, and AVP was quantified in plasma aliquots obtained from the whole blood samples. A marked decline in mean AVP plasma levels from 5.4+/-2.7 ng/l during flaccidity to 2.9+/-2.5 ng/l during rigidity was registered in the systemic blood of the subjects. No further decline was observed when the rigid penis became detumescent. In contrast, no alterations in AVP plasma levels were detected in the cavernous blood under the different penile conditions. The results from our study are contrary to the hypothesis of a local release and uptake of AVP in the cavernous compartment in the control of penile flaccidity and detumescence. Moreover, our findings are not in favour of AVP as an important mediator involved in adrenergic neurotransmission in the corpus cavernosum penis. Nevertheless, our data indicate that the decrease in systemic AVP levels in response to sexual arousal might be a prerequisite to facilitate penile tumescence and rigidity in healthy males.     

Single-dose tranexamic acid reduces postoperative bleeding after coronary surgery in patients treated with aspirin until surgery

Tranexamic acid reduces postoperative bleeding after coronary artery bypass grafting. We evaluated the effects of a single dose of tranexamic acid given immediately before cardiopulmonary bypass (CPB) in patients treated with aspirin until the day before surgery. The study was a prospective, randomized, double-blinded, placebo-controlled, parallel-group trial. Eighty patients were included and divided into two groups: one group received tranexamic acid 30 mg/kg, and one group received placebo (0.9% NaCl) as a bolus injection before CPB. Postoperative blood loss was recorded for 16 h. Transfusions of blood products were recorded for the whole hospital stay. Transfusions of packed red cells were given when the hematocrit value was less than 20% during CPB and less than 25% after surgery. The patients in the tranexamic acid group had significantly less postoperative bleeding compared with the patients in the placebo group (mean [SD]) (475 [274] mL versus 713 [243] mL; P < 0.001). An effective inhibition of fibrinolysis was found in patients receiving tranexamic acid. Tranexamic acid reduces postoperative bleeding in coronary artery bypass grafting patients treated with aspirin until the day before surgery. IMPLICATIONS: Continuation of aspirin medication until the day before coronary artery bypass grafting may increase postoperative bleeding. The administration of a single dose of tranexamic acid (30 mg/kg) immediately before cardiopulmonary bypass significantly reduced postoperative bleeding and inhibited fibrinolysis in these patients.     

Intra-aneurysm pressure measurements in successfully excluded abdominal aortic aneurysm after endovascular repair

PURPOSE: This study was performed to determine intra-aneurysm sac pressure of abdominal aortic aneurysm after endovascular aneurysm repair in patients considered successfully treated with aneurysm shrinkage and absence of endovascular leakage. METHODS: In 10 patients with median aneurysm shrinkage of 12 mm (range, 7 to 22 mm) and median follow-up of 19 months (range, 14-43 months), a percutaneous translumbar intra-aneurysm pressure measurement was made with a 0.014-inch guide wire-mounted pressure sensor and compared with intra-aortic pressure. RESULTS: Median intra-aneurysm systolic/diastolic/mean pressure was 19/18/19 (range, 17-35/13-33/17-31) compared with median intra-aortic pressure of 135/75/99 (range, 126-199/60-95/84-129). Mean intra-aneurysm pressure was 20% of mean intra-aortic pressure (range, 13%-33%). Pulsatility was negligible. CONCLUSION: Successful endovascular aneurysm repair of abdominal aortic aneurysm results in considerable pressure reduction in the aneurysm sac. The ability to monitor intra-aneurysm pressure provides hemodynamic information within the sac, which can be used in conjunction with imaging to determine whether a secondary intervention is warranted.