A reliable method to assess the water permeability of a dialysis system: the global ultrafiltration coefficient.

Background: Recent randomized controlled trials suggest that sufficiently high convection post-dilutional haemodiafiltration (HC-HDF) improves survival in dialysis patients, consequently this technique is increasingly being adopted. However, when performing HC-HDF, rigorous control systems of the ultrafiltration setting are required. Assessing the global ultrafiltration coefficient of the dialysis system [GKD-UF; defined as ultrafiltration rate (QUF)/transmembrane pressure] or water permeability may be adapted to the present dialysis settings and be of value in clinics. Methods: GKD-UF was determined and its reproducibility, variability and influencing factors were specifically assessed in 15 stable patients routinely treated by high-flux haemodialysis or HC-HDF in a single unit. Results: GKD-UF invariably followed a parabolic function with increasing QUF in dialysis and both pre- and post-dilution HC-HDF (R2 constantly >0.96). The vertex of the parabola, GKD-UF-max and related QUF were very reproducible per patient (coefficient of variation 3.9 ± 0.6 and 3.3 ± 0.3%, respectively) and they greatly varied across patients (31­42 mL/h−1/mmHg and 82­100 mL/min, respectively). GKD-UF-max and its associated QUF decreased during dialysis treatment (P < 0.01). The GKD-UF-max decrease was related to weight loss (R2 = 0.66; P = 0.0015). Conclusions: GKD-UF is a reliable and accurate method to assess the water permeability of a system in vivo. It varies according to dialysis setting and patient-related factors. It is an objective parameter evaluating the forces driving convection and identifies any diversion of the system during the treatment procedure. It is applicable to low- or high-flux dialysis as well as pre- or post-dilution HDF. Thus, it may be used to describe the characteristics of a dialysis system, is suitable for clinical use and may be of help for personalized prescription.

Treatment Response and Outcomes in Post-transplantation Lymphoproliferative Disease vs Lymphoma in Immunocompetent Patients.

Posttransplantation lymphoproliferative disorder (PTLD) after solid organ transplantation may carry a poorer prognosis than lymphoma in immunocompetent individuals, but comparative data are lacking. In a retrospective, single-center, case-control study, 21 cases of PTLD were identified in patients undergoing kidney transplantation since 2000, and compared to 42 nontransplanted controls cared for in the same institution and matched for age, prognostic index, and cerebral localization. Two-year and 5-year overall survival was 57% and 44%, respectively, in PTLD patients and 71% and 58% in controls (log-rank test P = .20). On multivariable analysis, overall survival was similar for PTLD and control patients (hazard ratio 1.71, 95% confidence interval 0.81 to 3.61, P = .16). Response rate to first-line chemotherapy was similar between the 2 groups. Death was due to progression of the disease in 46% vs 94% of PTLD and control patients, respectively (P < .01), or sepsis in 31% vs 0% (P = .03). Treatment-related mortality was significantly higher in PTLD (19%) than in controls (0%, P = .03). In conclusion, response to first-line chemotherapy and overall survival are similar in PTLD and control patients, whereas causes of death were significantly different. Better prevention and management of infectious complications could improve the results in PTLD patients.

Different classifications yield variance in metabolic syndrome prevalence and dynamics in renal transplant recipients.

INTRODUCTION: The metabolic syndrome (MS) is a combination of factors that are associated with increased cardiovascular diseases. High MS prevalence was reported in renal transplant recipients. However, little is known about the longitudinal prevalence and its dynamic properties in this population. We studied the longitudinal prevalence of MS at 3 and 12 months post-transplantation using 3 classifications. PATIENTS AND METHODS: We studied a cohort of 322 patients who underwent transplantation between 1996 and 2003 who had isotopic measurement of transplant glomerular filtration rate and MS assessment at 3 and 12 months after transplantation. Prevalence and change of MS status in terms of acquisition or regression were analyzed based on World Health Organization (WHO), International Diabetic Federation (IDF), and The Adult Treatment Panel-III (ATP-III) classifications. RESULTS: The prevalences at 3 and 12 months were as follows: WHO, 8.4% and 8.1%; IDF, 25.8% and 29.8%; and ATP-III, 34.3% and 36.6%, respectively. Change in MS status was noted in 9.7%, 16.4%, and 20.5% of subjects within WHO, IDF, and the ATP-III classifications, respectively. Prevalence was significantly lower with WHO than IDF and ATP-III. Prevalence was the highest with ATP-III. However, the difference with IDF was significant only at 3 months post-transplantation. Depending on the classification used, 10%-21% of subjects change MS status within the first year of transplantation. CONCLUSION: Longitudinal analysis confirms the high prevalence of MS and also highlights the dynamics of MS. We think both prevalence and dynamics should be accounted for when studying outcomes.

An epidemic of Pneumocystis jiroveci pneumonia in a renal transplantation center: role of T-cell lymphopenia.

Although only 2 cases of Pneumocystis jiroveci pneumonia were observed in our center between 2004 and 2009, we diagnosed 9 cases in 2010. Each patient had been in contact in the hospital with at least 1 other patient suffering P jiroveci pneumonia. Genotyping of P jiroveci pneumonia strains demonstrates a total homogeneity of the DNA sequences in the 7 patients already analyzed. CD4+ lymphocyte count was significantly lower at M3 in P jiroveci pneumonia patients than in controls. Our clinical and molecular data confirm that interhuman transmission of P jiroveci is possible, particularly to lymphopenic transplant recipients.

Monthly screening for BK viremia is an effective strategy to prevent BK virus nephropathy in renal transplant recipients.

BACKGROUND: BK polyomavirus virus (BKV) nephropathy (BKVN) is the most common viral infection that affects renal allografts. Because a specific antiviral therapy is lacking, BKVN may result in graft dysfunction and/or loss. We prospectively analyzed whether monthly nucleic acid testing (NAT) for BKV replication in blood and immediate reduction of immunosuppression (IS) could prevent BKVN. METHODS: NAT was performed at monthly intervals for 6 months and then at 12 months in 119 de novo renal transplant recipients. In viremic patients (presumptive BKVN), a graft biopsy was systematically performed and IS was immediately reduced. RESULTS: BKV viremia occurred in 13 (10.9%) patients after a median time of 90 days (23-241); 77% of patients were viremic before month 4. After reduction of IS, viral load was undetectable in 11 patients, remained low in 1, and continued to increase in 1 patient who developed definitive BKVN despite reduction of IS, and finally returned to dialysis 6 months after transplantation. CONCLUSION: BKV infection is an early complication. Monthly NAT in blood during the first 6 months and immediate reduction of IS in viremic patients almost completely prevent definitive BKVN.

Evolution of coronary artery calcifications following kidney transplantation: relationship with osteoprotegerin levels.

We prospectively assessed the evolution of coronary artery calcification (CAC) and osteoprotegerin (OPG) levels after renal transplantation (RT). Eighty-three recipients were followed-up prospectively during 1 year. Blood was collected before (baseline) and after RT for determination of mineral metabolism parameters including OPG. CAC was measured by multidetector computed tomography at transplantation (baseline) and 1 year later. Progression of CAC was defined as a difference between the follow-up square-root transformed volume (SRV) and the baseline SRV >or= 2.5. By multivariate analysis, baseline OPG level, age and low LDL levels were significantly associated with baseline CAC. RT was accompanied by mineral metabolism improvement with a decrease of OPG from 955 [395-5652] to 527 [217-1818] pg/mL and parathyroid hormone from 94 [1-550] to 62 [16-410] pg/mL. Thirty-one percent of patients did not exhibit CAC at baseline. CAC diminished in 14.5%, stabilized in 59.2% and progressed in 26.3% of patients. Baseline CAC was associated with progression (OR 2.92 [1.02-8.36]). No significant association was found between OPG and CAC progression despite a higher baseline OPG level in progressors (1046 [456-3285]) vs. non-progressors (899 [396-5952] pg/mL). CAC at baseline, but not 1 year after RT, is independently associated with baseline OPG; posttransplant CAC progression is predicted by baseline CAC score.

Ischemic postconditioning prevents ischemic acute renal failure.

INTRODUCTION: Delayed graft function (DGF), a frequent complication after kidney transplantation, decreases graft survival. Ischemia/reperfusion (I/R) injuries play a major role in DGF pathophysiology. Because ischemic postconditioning (IP) is efficient to prevent myocardial I/R injuries and reduce infarct size, we sought to describe renal effects of IP. MATERIALS AND METHODS: Swiss mice were divided into three groups after left nephrectomy. Thirty minutes of right kidney ischemia followed by three cycles of 30 seconds of ischemia and reperfusion (IP group: n = 12) versus immediate reperfusion (n = 7). Left nephrectomized and right kidney sham operated mice were used as control groups (n = 6). Mice were followed for an 8-day survival analysis. Serum levels of creatinine and protein as well as weights were determined 2 days before and at days 2 and 8 after surgery. RESULTS: IP improved kidney function on day 2; the mean serum creatinine level was 1.25 +/- 0.71 versus 2.9 +/- 1.3 mg/dL in the immediate reperfusion group (P < .02). We also observed a trend toward increased animal survival (25% vs. 0% in the immediate reperfusion group; P = .10). Despite a significant increase in proteinuria among all groups, there was no significant difference. CONCLUSION: In a mouse model, IP seems to prevent postischemic acute renal failure after 30 minutes of kidney ischemia.

Technical aspects of catheter-related interventions in the liver of the rabbit.

PURPOSE: On the basis of 89 different vascular interventions performed in the livers of 39 rabbits, we attempted to establish the feasibility and technical limitations of these procedures. MATERIAL AND METHODS: Forty-five selective hepatic artery catheterizations were carried out using 0.66-mm and 1.0-mm catheters, including superselective proper hepatic catheterizations (n = 14) using a specially designed 0.66-mm introducer/catheter system. The portal system was investigated with both direct (n = 5) and indirect (arterial) (n = 4) portography. Hepatic, vein catheterizations were performed in 22 cases. RESULTS: With the 0.66-mm system, spasm occurred in one of 11 cases in the proper hepatic artery, and no spasm was observed in the common hepatic and celiac arteries. Both arterial portography and hepatic venography were easily performed and were a precise and repeatable method. CONCLUSION: The 0.66-mm system has proved to be advantageous over the 1.0-mm catheterization in avoiding arterial spasm. Direct portography as well as catheterization of the hepatic vein from a jugular approach are hazardous, leading to serious complications including the death of the animal.

Behçet's syndrome/AIDS/cerebral toxoplasmosis: an unusual association.

Few cases of AIDS associated to manifestations suggesting Behçet's syndrome have been reported. This case is of a young married woman who presented, during a period of 7 years, clinical manifestations consistent with the late diagnosis of Behçet's syndrome, when she developed recurrent lymphomonocytic meningoencephalitis. At this time, she was found to be infected by HIV-1. Immunosuppressive doses of glucocorticoid produced an unsatisfactory response and she evolved to death due to CNS toxoplasmosis. The latter diagnosis was presumed on the basis of magnetic resonance imaging findings and proved by necropsy after her third hospital stay. One of the factors hindering the appropriate diagnosis was the low level of CD4 and the CD4/CD8 ratio, sometimes observed in active Behçet's syndrome and higher than those observed in patients with this severe opportunistic infection. No information about the exact period of time she had been infected with HIV-1 is available. So, we do not know whether both diseases were overlooked, if the patient, infected by HIV-1, developed an unusual clinical feature consistent with Behçet's Behçet's syndrome, and subsequently evolved to AIDS.

Antiinflammatory agents protect opossum esophagus during radiotherapy.

Eighteen opossums received 2250 rad 60Co to the entire esophagus and lower esophageal sphincter. Animals received treatment with 600 mg aspirin, 25 mg/kg hydrocortisone, or saline before irradiation and twice daily for 1 week after irradiation. At 10 days postirradiation, animals were evaluated for signs of acute esophagitis by esophagoscopy and barium esophagram. Each animal was then killed and the esophagus removed and evaluated histologically. Animals treated with either aspirin or hydrocortisone had significantly milder esophagitis than control irradiated animals.

The radiology research technologists: who are they?

Over the years, radiology research has expanded its application due to the tremendous advances in imaging technology and the expanding role of the radiologist in the care and management of the patient. This paper is intended to provide insight into the activities and role of the radiologic technologist in radiology research today.

The coil baffle in the experimental occlusion of large vascular structures.

A new method to occlude large vascular systems using a combination of a coil baffle and conventional coil was evaluated in the abdominal aortas of seven dogs. Three types of coil baffles were introduced into the canine abdominal aorta, followed by four to eight coils. Balloon catheters were applied to control the length of the embolus complex in two dogs. All seven dogs had complete aortic occlusion immediately. Six dogs were observed for six weeks; of these four required additional Gelfoam embolization at two weeks. At autopsy, all six dogs had 100% aortic occlusion. The combined use of coil baffle and coil allows occlusion of large vascular systems not feasible for occlusion with the conventional coil alone.

Improved image quality and examination procedures in xeroradiographic peripheral angiography: an experimental study.

Ten dogs were used to compare conventional peripheral angiography and xeroradiographic angiography using three different concentrations of contrast material. Serial angiograms were produced in order to determine maximum arterial filling time, and a xeroradiograph was made at the predetermined maximal arterial phase. Xeroradiographic angiography consistently provided better imaging of the peripheral vessels and soft tissue. Reduction of the concentration of contrast material resulted in the loss of an image of diagnostic quality using conventional angiography, but vascular definition was maintained using xeroradiography. These studies indicate that xeroradiographic angiography not only improved peripheral vascular imaging, but is also successful at a lower concentration of contrast material, thus reducing toxic systemic effects and pain associated with the procedure.

Radiation esophagitis in the opossum: radioprotection with indomethacin.

Twenty-five opossums (Didelphis virginiana) were evaluated before irradiation by fiberoptic endoscopy and air-contrast barium esophagram examination. All animals received 2250 rad 60Co-irradiation in a single exposure to the entire esophagus and lower exophageal sphincter. Animals received treatment with indomethacin before and daily for 1 wk postirradiation of 16, 16-dimethylprostaglandin E2 before irradiation and every 4 hr for 24 hr postirradiation. Control animals received only injection vehicle. Acute esophagitis occurred 7--10 days postirradiation in control animals and was characterized by erythema, ulceration, and sloughing of esophageal mucosa as determined by air-contrast barium esophagram, endoscopy, and histology. Prostaglandin-treated animals showed more severe evidence of esophagitis than control animals. Indomethacin-treated animals showed no signs or only mild esophagitis posttreatment. It is concluded that indomethacin treatment may significantly reduce the severity of radiation esophagitis perhaps by blockade of prostaglandin synthesis.

A technique for barium esophagram in the opossum.

Single and double contrast barium esophagram examinations were performed on 42 opossums. Each animal was anesthetized with pentabarbital sodium, a catheter was placed in the esophagus, and barium or barium and air were injected into the esophagus. Two radiographs per second for 7 seconds were taken. The radiographs were reproducible and of high quality.

The opossum as an animal model for studying radiation esophagitis.

Six opossums were evaluated as a possible animal model of radiation esophagitis. In a single exposure to the esophagus, four animals received 60Co radiation of various doses; two served as controls. Pre- and postirradiation evaluations using fiberoptic endoscopy, mucosal biopsy, barium esophagography, and manometry were performed. Esophagitis developed at one week in irradiated animals. Opossums receiving 17.5, 20, and 22.5 Gy (1,750; 2,000; and 2,250 rad) became anorexic one week postirradiation, and abnormal motility subsequently developed. The controls and the animal receiving 15 Gy (1,500 rad) remained normal. Histological changes in the irradiated opossum esophagus resembled those found in humans.