Renal oxygenation changes during acute unilateral ureteral obstruction: assessment with blood oxygen level-dependent mr imaging--initial experience

PURPOSE: To prospectively determine if changes in intrarenal oxygenation during acute unilateral ureteral obstruction can be depicted with blood oxygen level-dependent (BOLD) magnetic resonance (MR) imaging. MATERIALS AND METHODS: The study was approved by the local ethics committee, and written informed consent was obtained from all patients. BOLD MR imaging was performed in 10 male patients (mean age, 45 years +/- 17 [standard deviation]; range, 20-73 years) with a distal unilateral ureteral calculus and in 10 healthy age-matched male volunteers to estimate R2*, which is inversely related to tissue Po(2). R2* values were determined in the cortex and medulla of the obstructed and the contralateral nonobstructed kidneys. To reduce external effects on R2*, the R2* ratio between the medulla and cortex was also analyzed. Statistical analysis was performed with nonparametric rank tests. P < .05 was considered to indicate a significant difference. RESULTS: All patients had significantly lower medullary and cortical R2* values in the obstructed kidney (median R2* in medulla, 10.9 sec(-1) [range, 9.1-14.3 sec(-1)]; median R2* in cortex, 10.4 sec(-1) [range, 9.7-11.3 sec(-1)]) than in the nonobstructed kidney (median R2* in medulla, 17.2 sec(-1) [range, 14.6-23.2 sec(-1)], P = .005; median R2* in cortex, 11.7 sec(-1) [range, 11.0-14.0 sec(-1)], P = .005); values in the obstructed kidneys were also significantly lower than values in the kidneys of healthy control subjects (median R2* in medulla, 16.1 sec(-1) [range, 13.9-18.1 sec(-1)], P < .001; median R2* in cortex, 11.6 sec(-1) [range, 10.5-12.9 sec(-1)], P < .001). R2* ratios in the obstructed kidneys (median, 1.06; range, 0.85-1.27) were significantly lower than those in the nonobstructed kidneys (median, 1.49; range, 1.26-1.71; P = .005) and those in the kidneys of healthy control subjects (median, 1.38; range, 1.23-1.47; P < .001). In contrast, R2* ratios in the nonobstructed kidneys of patients were significantly higher than those in kidneys of healthy control subjects (P = .01). CONCLUSION: Increased oxygen content in the renal cortex and medulla occurs with acute unilateral ureteral obstruction, suggesting reduced function of the affected kidney.

Low prevalence of atrial fibrillation in asymptomatic adults in Geneva, Switzerland

Aims To determine the prevalence of atrial fibrillation (AF) in a population-based sample of adults. Methods and results Between January 2005 and December 2007 individuals aged >/=50 years, residents of the city of Geneva, who had participated in a previous random survey were invited for follow-up examination. AF was assessed on a single resting 6-lead ECG. Reported prevalences were standardized for the age distribution of Canton Geneva. Overall participation was 72.8%. Twenty-nine cases of AF (22 men) were diagnosed among 3285 subjects (1696 men). The crude prevalence of AF (95% CI) was 0.88% (0.86, 0.90) overall, but higher in men [1.30% (1.26, 1.34)] than in women [0.44% (0.41, 0.47)]. The age-standardized AF prevalence was slightly higher [overall: 0.94% (0.91, 0.97), men: 1.23% (1.19, 1.27), women: 0.54% (0.47, 0.61)]. AF prevalence increased with age in both sexes. A 'history of suspected arterial embolism' (brain or legs) was higher in the AF cases (10.3 vs. 3.3%; P = 0.03). Conclusion This population-based survey of a general Swiss population indicates that the prevalence of AF remains below 1%. These results are less alarming than those from previous studies based on patients seeking medical care.

Oral examination and radiographic evaluation of the dentition in wild cats from Namibia

Feline tooth resorption has been widely reported in domestic cats and sporadically described in other felidae. The goal of the present study was to determine the prevalence of tooth resorption and to report other dental problems in a population of wild felidae. Observations of dental disorders and anomalies were made in skulls from 73 wild felidae (cheetahs, leopards, caracals, African wildcats, and lions) originating from Namibia. In addition, radiographs were taken in 43 cases to determine signs of bone and root pathology. Radiographs showed varying stages of tooth resorption in 16.0% of the specimens. Other dental anomalies found included fused teeth, supernumerary roots, or missing teeth. The prevalence of dental resorption in wild felidae was lower than reported in the domestic cat.

Xenograft rejection: IgG1, complement and NK cells team up to activate and destroy the endothelium

Acute vascular rejection represents a formidable barrier to clinical xenotransplantation and it is known that this type of rejection can also be initiated by xenoreactive antibodies that have limited complement-activating ability. Using a sophisticated mouse model, a recent study has provided in vivo evidence for the existence of an IgG(1)-mediated vascular rejection, which uniquely depends on both the activation of complement and interactions with FcgammaRIII on natural killer (NK) cells.

Decompressive hemicraniectomy in subarachnoid haemorrhage: the influence of infarction, haemorrhage and brain swelling

OBJECTIVE: To analyse decompressive hemicraniectomy (DHC) in patients with aneurysmal subarachnoid haemorrhage (SAH) with regard to infarction, haemorrhage or brain swelling. METHODS: DHC was performed in 43 of 787 patients with SAH. Patients were stratified according to (1) primary brain swelling without and (2) with additional intracerebral haematoma, (3) secondary brain swelling without rebleeding or infarcts and (4) with infarcts or (5) with rebleeding. Outcome was assessed according to the modified Rankin scale at 6 months RESULTS: Overall, 36 of 43 patients (83.7%) with DHC and 241 of 744 patients (32.4%) without DHC have been of a poor grade on admission (World Federation of Neurological Societies grading 4-5; p<0.0001). Favourable outcome was achieved in 11 of 43 (25.6%) patients with DHC. There was no difference in favourable outcome after primary (25%) versus secondary (26.1%) DHC (p = 1.0). Subgroup analysis (brain swelling vs bleeding vs infarcts) revealed no difference in the rate of favourable outcome. In a multivariate analysis, acute hydrocephalus (p = 0.02) and clinical herniation (p = 0.03) were significantly associated with unfavourable outcome. CONCLUSIONS: We conclude that primary and secondary hemicraniectomy may be warranted, irrespective of the underlying aetiology-infarction, haemorrhage or brain swelling. The time from onset of intractable ICP to DHC seems to be crucial, rather than the time from SAH to DHC.

Dual-energy X-ray absorptiometry for measuring total bone mineral content in the rat: study of accuracy and precision

Sequential studies of osteopenic bone disease in small animals require the availability of non-invasive, accurate and precise methods to assess bone mineral content (BMC) and bone mineral density (BMD). Dual-energy X-ray absorptiometry (DXA), which is currently used in humans for this purpose, can also be applied to small animals by means of adapted software. Precision and accuracy of DXA was evaluated in 10 rats weighing 50-265 g. The rats were anesthetized with a mixture of ketamine-xylazine administrated intraperitoneally. Each rat was scanned six times consecutively in the antero-posterior incidence after repositioning using the rat whole-body software for determination of whole-body BMC and BMD (Hologic QDR 1000, software version 5.52). Scan duration was 10-20 min depending on rat size. After the last measurement, rats were sacrificed and soft tissues were removed by dermestid beetles. Skeletons were then scanned in vitro (ultra high resolution software, version 4.47). Bones were subsequently ashed and dissolved in hydrochloric acid and total body calcium directly assayed by atomic absorption spectrophotometry (TBCa[chem]). Total body calcium was also calculated from the DXA whole-body in vivo measurement (TBCa[DXA]) and from the ultra high resolution measurement (TBCa[UH]) under the assumption that calcium accounts for 40.5% of the BMC expressed as hydroxyapatite. Precision error for whole-body BMC and BMD (mean +/- S.D.) was 1.3% and 1.5%, respectively. Simple regression analysis between TBCa[DXA] or TBCa[UH] and TBCa[chem] revealed tight correlations (n = 0.991 and 0.996, respectively), with slopes and intercepts which were significantly different from 1 and 0, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Improved safety and reduction in stent thrombosis associated with biodegradable polymer-based biolimus-eluting stents versus durable polymer-based sirolimus-eluting stents in patients with coronary artery disease: final 5-year report of the LEADERS (Limus Eluted From A Durable Versus ERodable Stent Coating) randomized, noninferiority trial

OBJECTIVES This study sought to report the final 5 years follow-up of the landmark LEADERS (Limus Eluted From A Durable Versus ERodable Stent Coating) trial. BACKGROUND The LEADERS trial is the first randomized study to evaluate biodegradable polymer-based drug-eluting stents (DES) against durable polymer DES. METHODS The LEADERS trial was a 10-center, assessor-blind, noninferiority, "all-comers" trial (N = 1,707). All patients were centrally randomized to treatment with either biodegradable polymer biolimus-eluting stents (BES) (n = 857) or durable polymer sirolimus-eluting stents (SES) (n = 850). The primary endpoint was a composite of cardiac death, myocardial infarction (MI), or clinically indicated target vessel revascularization within 9 months. Secondary endpoints included extending the primary endpoint to 5 years and stent thrombosis (ST) (Academic Research Consortium definition). Analysis was by intention to treat. RESULTS At 5 years, the BES was noninferior to SES for the primary endpoint (186 [22.3%] vs. 216 [26.1%], rate ratio [RR]: 0.83 [95% confidence interval (CI): 0.68 to 1.02], p for noninferiority <0.0001, p for superiority = 0.069). The BES was associated with a significant reduction in the more comprehensive patient-orientated composite endpoint of all-cause death, any MI, and all-cause revascularization (297 [35.1%] vs. 339 [40.4%], RR: 0.84 [95% CI: 0.71 to 0.98], p for superiority = 0.023). A significant reduction in very late definite ST from 1 to 5 years was evident with the BES (n = 5 [0.7%] vs. n = 19 [2.5%], RR: 0.26 [95% CI: 0.10 to 0.68], p = 0.003), corresponding to a significant reduction in ST-associated clinical events (primary endpoint) over the same time period (n = 3 of 749 vs. n = 14 of 738, RR: 0.20 [95% CI: 0.06 to 0.71], p = 0.005). CONCLUSIONS The safety benefit of the biodegradable polymer BES, compared with the durable polymer SES, was related to a significant reduction in very late ST (>1 year) and associated composite clinical outcomes. (Limus Eluted From A Durable Versus ERodable Stent Coating [LEADERS] trial; NCT00389220).

Spatio-temporal dynamics of alpha brain electric fields, and cognitive modes

Brian electric activity is viewed as sequences of momentary maps of potential distribution. Frequency-domain source modeling, estimation of the complexity of the trajectory of the mapped brain field distributions in state space, and microstate parsing were used as analysis tools. Input-presentation as well as task-free (spontaneous thought) data collection paradigms were employed. We found: Alpha EEG field strength is more affected by visualizing mentation than by abstract mentation, both input-driven as well as self-generated. There are different neuronal populations and brain locations of the electric generators for different temporal frequencies of the brain field. Different alpha frequencies execute different brain functions as revealed by canonical correlations with mentation profiles. Different modes of mentation engage the same temporal frequencies at different brain locations. The basic structure of alpha electric fields implies inhomogeneity over time — alpha consists of concatenated global microstates in the sub-second range, characterized by quasi-stable field topographies, and rapid transitions between the microstates. In general, brain activity is strongly discontinuous, indicating that parsing into field landscape-defined microstates is appropriate. Different modes of spontaneous and induced mentation are associated with different brain electric microstates; these are proposed as candidates for psychophysiological ``atoms of thought''.