The functional anatomy of semantic retrieval is influenced by gender, menstrual cycle, and sex hormones

This study examines the neurobiology of semantic retrieval and describes the influence of gender, menstrual cycle, and sex hormones on semantic networks. Healthy right-handed subjects (12 men, 12 women) were investigated with 3T-fMRI during synonym generation. Behavioral performance and sex hormone levels were assessed. Women were examined during the early follicular and midluteal cycle phase. The activation pattern in all groups involved left frontal and temporal as well as bilateral medial frontal, cingulate, occipital, basal ganglia, and cerebellar regions. Men showed greater left frontal activation than women in both menstrual cycle phases. Women yielded high correlations of left prefrontal activation with estradiol in the midluteal phase and with progesterone in both phases. Testosterone levels correlated highly with left prefrontal activation in all three groups. In all, we describe a cerebral network involved in semantic processing and demonstrate that it is significantly affected by gender and sex steroid hormones

beta(2)-Microglobulin and Phosphate Clearances Using a Wearable Artificial Kidney: A Pilot Study

Background: Additional small-solute clearances during standard thrice-weekly hemodialysis treatments have not improved patient survival. However, these treatments have limited middle-molecule clearances. Thus, newer therapies designed to increase middle-molecule clearances need to be developed and evaluated. Study Design: Pilot clinical trial to measure beta(2)-Microglobulin and phosphate clearances with a wearable hemodialysis device. Setting & Participants: 8 regular hemodialysis patients under the care of a university teaching hospital. Intervention: Patients were fitted with a wearable hemodialysis device for 4 to 8 hours. Outcomes: All patients tolerated the treatment. Results: Average amount of beta(2)-microglobulin removed was 99.8 +/- 63.1 mg, with mean clearance of 11.3 +/- 2.3 mL/min, and an average of 445.2 +/- 326 mg of phosphate was removed, with mean plasma phosphate clearance of 21.7 +/- 4.5 mL/min. These clearances compared favorably with mean urea and creatinine plasma clearances (21.8 +/- 1.6 and 20.0 +/- 0.8 mL/min, respectively). Limitations: Proof-of-concept preliminary trial. Additional studies are warranted to confirm these positive preliminary data. Conclusions: This wearable artificial kidney potentially provides effective beta(2)-microglobulin and phosphate clearances and, by analogy, middle-molecule clearances. Am J Kidney Dis 54:104-111. (c) 2009 by the National Kidney Foundation, Inc

A wearable haemodialysis device for patients with end-stage renal failure: a pilot study

Background More frequent haemodialysis can improve both survival and quality of life of patients with chronic kidney disease. However, there is little capacity in the UK to allow patients to have more frequent haemodialysis treatments in hospital and satellite haemodialysis units. New means of delivering haemodialysis are therefore required. Our aim was to assess the safety and efficiency of a wearable haemodialysis device. Methods Eight patients with end-stage kidney failure (five men, three women, mean age 51.7 [SD 13.8] years) who were established on regular haemodialysis were fitted with a wearable haemodialysis device for 4-8 h. Patients were given unfractionated heparin for anticoagulation, as they would be for standard haemodialysis. Findings There were no important cardiovascular changes and no adverse changes in serum electrolytes or acid-base balance. There was no evidence of clinically significant haemolysis in any patient. Mean blood flow was 58 . 6 (SD 11 . 7) mL/min, with a dialysate flow of 47.1 (7.8) mL/min. The mean plasma urea. clearance rate was 22.7 (5.2) mL/min and the mean plasma creatinine clearance rate was 20.7 (4-8) mL/min. Clotting of the vascular access occurred in two patients when the dose of heparin was decreased and the partial thromboplastin time returned towards the normal reference range in both of these patients. The fistula needle became dislodged in one patient, but safety mechanisms prevented blood loss, the needle was replaced, and treatment continued. Interpretation This wearable haemodialysis device shows promising safety and efficacy results, although further studies will be necessary to confirm these results

A wearable hemofilter for continuous ambulatory ultrafiltration

Ultrafiltration is effective for treating fluid overload, but there are no suitable machines for ambulatory treatment. This study summarizes the use of a light-weight wearable continuous ambulatory ultrafiltration device consisting of a hollow fiber hemofilter, a battery operated pulsatile pump, and two micropumps to control heparin administration and ultrafiltration. Six volume-overloaded patients underwent ultrafiltration for 6 h with treatment discontinued in one patient due to a clotted catheter. Blood flow averaged 116 ml min(-1), the ultrafiltration rate ranged from 120-288 ml h(-1) with about 150 mmol of sodium removed. Blood pressure, pulse, and biochemical parameters remained stable with no significant hemolysis or complications. Our data show that the wearable hemofilter appears to be safe, effective, and practical for patients. This device could have a major impact on the quality of life of fluid-overloaded patients with heart failure. Additional studies will be needed to confirm these initial promising results