Effects of long-term ambient ozone exposure on biomass and wood traits in poplar treated with ethylenediurea (EDU).

This is the longest continuous experiment where ethylenediurea (EDU) was used to protect plants from ozone (O3). Effects of long-term ambient O3 exposure (23 ppm h AOT40) on biomass of an O3 sensitive poplar clone (Oxford) were examined after six years from in-ground planting. Trees were irrigated with either water or 450 ppm EDU. Above (-51%) and below-ground biomass (-47%) was reduced by O3 although the effect was significant only for stem and coarse roots. Ambient O3 decreased diameter of the lower stem, and increased moisture content along the stem of not-protected plants (+16%). No other change in the physical wood structure was observed. A comparison with a previous assessment in the same experiment suggested that O3 effects on biomass partitioning to above-ground organs depend on the tree ontogenetic stage. The root/shoot ratios did not change, suggesting that previous short-term observations of reduced allocation to tree roots may be overestimated.

[On-line haemodiafiltration with sorbent-regenerated ultrafiltrate as replacement fluid: Beta2-microglobulin removal versus filtration fraction]. / Emodiafiltrazione on-line con reinfusione endogena (HFR): rimozione di Beta2-microglobulina (Beta2-m) vs frazione di filtrazione (FF%).

PURPOSE: In order to encourage the removal of middle molecules in hemodiafiltration (HDF) techniques an attempt is made to maximize convective clearance by increasing the ultrafiltration rate. However, convective clearance is limited by the maximum filtration fraction (FF%) obtainable, by the pre- or post reinfusion method and by the convective surface and the capacity of the filter used. This study aimed to evaluate the effect of the FF% in the removal of Beta2-microglobulin (Beta2-m) during hemodiafiltration reinfusion (HFR) to identify the best ultrafiltration strategies; and therefore, a better removal of medium molecular weight solutes in this hemodiafiltrative technique recently introduced in clinical practice. METHODS: Ten chronic uremic patients (eight males, two females; age 66 +/- 18 yrs) already on renal dialysis therapy (RDT) for 80 +/- 36 months, were subjected to four HFR sessions, with Td=240 +/- 10 min, Qb=312 +/- 18 and Qd=500 mL/min; the reinfusion rates (Qr) used were 43.6 +/- 7.2 mL/min (25-58) with FF% rates varying from 20-34 (24.2 +/- 3.8) for hematocritic levels of 34.6 +/- 4.2% at the start of the dialysis session. For each session the intradialytic reduction rates (RR%) of urea, creatinine (Cr), phosphate, uric acid and Beta2-m and its average clearance (KBeta2-m mL/min) were evaluated. RESULTS: The results obtained gave a RR% for urea of 69.4 +/- 5 (Kt/Veq=1.23 +/- 0.2) and for Cr, phosphate and uric acid values of, respectively, 61.2 +/- 5.4, 47.5 +/- 10 and 75.8 +/- 6.7. The intradialytic reductions in Beta2-m were 49.3 +/- 10.3% with a variability range from 29-69% and with average KBeta2-m values of 63.8 +/- 13.5 mL/min. The RR% of ss2-m and KBeta2-m were inversely correlated (p<0.01) to the FF% rate applied during the treatment; 75% of the HRF sessions in which we observed a reduction in Beta2-m levels >40% were those where a FF% between 20 and 26% was applied. CONCLUSIONS. From our study, it appears that in HFR the best ultrafiltration strategy from the convective sector in removing Beta2-m has FF% values in the range 20-26%. The occurrence of lower intradialytic reductions of Beta2-m with increasing FF% can be interpreted as a consequence of phenomena related to high intradialytic hemoconcentrations, to the excessive increase in the TMP and/or the increase in the protein cake with a consequent reduction in permeability and mass transfer. Although using a limited convective surface with a limited possibility of increasing the FF%, nevertheless, HFR seems capable of ensuring a satisfactory uremic toxin removal of low and medium molecular weight, which combined with the high biocompatibility deriving from the use of reinfused endogen, can be considered an effective dialytic strategy for preventing or retarding the complications in dialytic patients.

[Long-term use of Profiler in patients with dialysis intolerance: 8 months follow-up]. / Impiego a lungo termine del Profiler nei pazienti con intolleranza dialitica: follow-up a 8 mesi.

PURPOSE: A new method of profiled dialysis has been set up for many years in the Department of Nephrology, Dialysis and Renal Transplantation at the University of Bologna. This profiled dialysis is based on the use of a new kinetic mathematical model, in collaboration with the Faculty of Engineering at the University of Bologna, for the elaboration of individual sodium and ultrafiltration profiles. OBJECTIVE: The profiled dialysis aims are: 1) to stabilize the intradialytic blood volume, boosting the refilling of plasma water from the intracellular and the extravascular to the extracellular/intravascular compartments, to balance the ultrafiltration; 2) to counteract the disequilibrium syndrome reducing the shift of water from the extra to the intracellular compartment. The pre-dialysis elaboration of profiles is completely automatic and supported by a computerized programme, Profiler, which has been included in the software of the dialysis machine Bellco Formula 2000 Plus. METHODS: In this prospective and multicenter study, this profiled dialysis, performed according to the Profiler, was continuously applied, for an 8-month period, in a group of 13 hemodialysis (HD) patients with an intolerance to previous dialysis treatment. During the study, the following parameters were evaluated, comparatively, with the patient's basal treatment: a) sodium and water balance; b) percentage incidence of intradialytic complications such as hypotensive events, cramps, headache, and vomiting and; c) metabolic and nutritional status. RESULTS: Results evaluated in comparison with the patient's previous dialysis treatments, demonstrated: a) plasma sodium from 136.8 +/- 3 to 136.8 +/- 1.7 mEq/L (p=ns), dry body weight from 72.2 +/- 19.3 to 71.7 +/- 19.5 kg (p=ns), heart index from 3.7 +/- 0.7 to 3.1 +/- 0.5 L/min/m2 (p=ns), reactance from 5.3 +/- 15 to 4.9 +/- 11 ohm (p<0.05); b) incidence of intradialytic hypotensive events reduced from 64 to 4% (p<0.001), cramps reduced from 8 to 1% (p<0.01); c) plasma albumin from 3.5 +/- 0.2 to 3.7 +/- 0.3 g/dL (p=ns), Kt/Veq from 1.3 +/- 0.1 to 1.36 +/- 0.2 (p=ns). CONCLUSIONS: Patients treated with profiled dialysis had a higher stability of intradialytic blood pressure (BP) achieving a reduction in the incidence of disequilibrium syndrome symptoms, in comparison with previous treatment. These clinical intradialytic improvements were not correlated to clinical, instrumental or biochemical indexes of sodium-water overload nor to a worst dialysis adequacy and nutritional state.

Longitudinal assessment of body composition in CAPD patients using bioelectric impedance analysis. A comparison with hemodialysis patients.

The utility of bioelectric impedance analysis was assessed for longitudinal evaluation of body composition in two groups of uremic patients, one on CAPD and one on hemodialysis treatment, with no clinical marks of hyperhydration or infection. Nineteen CAPD patients (11 men 8 women) and 21 HD patients (12 men 9 women) were studied with bioelectric impedance analysis for a period of 12 months; total body water, fat free mass, and fat mass were calculated from bioelectric impedance analysis data of resistance and reactance at time 0 and 12 months later. No significant differences in body composition were found in the two groups at time 0 and 12 months later, with a similar trend for total body water, fat free mass, and fat mass. In CAPD, a significant increase in body weight was observed due mainly to a rise in fat mass, particularly evident in women with uremia. Bioelectric impedance analysis appears to be an instrument easily repeatable and reliable in CAPD and HD patients, reflecting at the same time body composition, the dialytic adequacy of a technique, and the patient's well being.

[The disease of beta 2-amyloid deposition in the differential diagnosis of juxta-articular subchondral geode lesions]. / La malattia da depositi di beta-2 amiloide nella diagnosi differenziale delle lesioni geodiche subcondrali iuxta-articolari.

Beta-2 amyloidosis deposition is a new type of amyloidosis recently observed in long-term hemodialysis patients. One of the major osteoarticular complications of this disease is the appearance of subchondral bone cysts. In this paper the radiologic features of such radiolucencies are described and the criteria are outlined of the differential diagnosis from the geodes found in other arthropathies or para-physiologic conditions. The importance of the status of the joint space is stressed: on the basis of its patterns, arthropathies may be grouped as follows: inhomogeneous space narrowing in degenerative arthritis; homogeneous space narrowing in inflammatory arthritis; normal or nearly normal joint space if there is no/not-prevalent involvement of articular cartilage.

Laser mirrors with variable reflected intensity and uniform phase shift: design process.

Optical coatings with circularly symmetric graded reflectance are used as laser mirrors in unstable resonators. A proper design of such coatings permits any maximum central reflectance to be obtained along with a null external reflectance. Different design approaches are discussed, and an optimized design that gives negligible distortion of the reflected and transmitted wave front is proposed. Coatings with super-Gaussian and step reflectance profiles are examined as two different solutions for improving laser beam quality.

Can teledialysis help in the clinical management of patients on remote hemodialysis?

This study investigated whether transmission of the parameters monitored from a remote center to the main center could improve the control of a dialysis session. The parameters of the computer connection module Monitral SC in remote and main centers, were transmitted by means of the Hospal data collection software (Demoplus) by modem, to the host computer. Each remote center can be temporarily disconnected, if necessary, from the telephone line and linked directly to a local computer. We checked 101 hemodialyses. The dialysis was monitored from filter washing to disconnection of the patients and the following parameters were selected: backfiltration during washing and hemodialysis: ultrafiltration, conductivity and temperature. From the sessions recorded (93%) we observed that backfiltration during the filter preparation phase was high (30%) in 28 sessions. Backfiltration during the preparatory phase is the major problem for correct management of dialysis sessions. The high percentage in which ultrafiltration had to be stopped shows that control of this parameter is still not ideal. Finally, the collection of monitor parameters and the comparative analysis of clinical data is useful for improving dialytic management.

Characterization and calibration of a variable-angle absolute reflectometer.

The instrument described is a newly designed reflectometer. Measurements are made with a polarized light beam as a function of wavelength and angle of incidence. Calibration tests have outlined the possibility of using the instrument for reflectance measurements on mirrors with good reproducibility (0.2%) and accuracy (better than 1%). This has been obtained by the alignment system of the sample and the absolute method used for the determination of its reflectance.

Technical and clinical evaluation of a new synthetic low flux polysulphon membrane for hemodialysis.

New synthetic membranes have been developed to reduce the ultrafiltration coefficient (Kf) maintaining an adequate permeability to medium-large solutes and a good biocompatibility. The new Fresenius F6 Low Flux Polysulphon Membrane is studied in this paper as far as hydraulic and permeability properties are concerned. For this purpose in vitro and in vivo tests have been carried out in a series of different conditions. In vitro sieving coefficients were near 1 for solutes with molecular weight up to 5000 Daltons. The ultrafiltration coefficient of the device was 5.4 ml/h/mmHg while the value of Kf normalized per square meter was lower than 5 ml/h/mmHg. The geometry of the blood path was adequate even operating at high blood flows without excessive resistance and obligate filtration. This resulted in vivo in a good performance during short dialysis schedules with good clearances of small and large molecules and with no risks of backfiltration. In fact, the low permeability to water permits constant operation with positive transmembrane pressures without excessive ultrafiltration rates. The biocompatibility of the membrane was excellent and high capacity of adsorption for beta-2 microglobulin was demonstrated. These results suggest that these membranes seem to be able to join the advantages of the traditional cellulosic membranes and of the newer synthetic membranes reducing their relative disadvantages.

Comparison of clinical and neurological status in elderly patients treated with two different hemodialysis techniques.

Five patients with a mean age of 63.4 years (range 62-67) who had frequent episodes of intradialytic intolerance during acetate hemodialysis (HDA) received biofiltration (BF). For each period of study (6 months on HDA and 6 months on BF), the patients underwent a complete clinical assessment, with evaluation of the electroencephalographic (EEG) pattern and acid-base status. During BF, we observed a reduction of hypotensive episodes (10% on BF vs. 26% on HDA) and EEG disturbances (18% on BF vs. 70% on HDA), with a more physiological correction of uremic acidosis. We conclude that BF improves clinical status and neurological tolerance with a better compensation of acidosis in the elderly.

Optical coatings with variable reflectance for laser mirrors.

Design procedures and fabrication techniques of variable reflectance dielectric mirrors for laser output couplers are proposed. The design criteria, based on the use of only one shaped layer in a multilayer structure, yield any peak value and shape of the reflectance profile. The deposition technique of the variable thickness layer consists of a sputtering process with a suitable mask interposed between the target and substrate. Results of a simple model that correlates the mirror parameters to mask diameter and position are presented. A few devices for a Nd:YAG laser have been proposed, characterized, and successfully tested in a laser resonator.

All-oxide broadband antireflection coatings by reactive ion plating deposition.

Coating experiments were made with reactive low-voltage ion plating to achieve the computer designed performance of all-oxide broadband antireflection systems on BK-7 glass. Reasonable accordance between calculated design and coating experiment as well as reliable production have been demonstrated.

The acid-base balance and the electroencephalographic pattern in patients on biofiltration treatment.

Electroencephalogram (EEG) monitoring and arterial blood gases was performed during biofiltration (BF) treatment and during conventional acetate hemodialysis (HDA). Biofiltration is an ultrashort hemodiafiltration with 3 liters of substitution fluid (Na+ 145 mEq/l, HCO-3 100 mEq/l). Our data show a better correction of acid-base balance during BF than during HDA. Moreover, we observe a lower incidence of EEG disturbancies on BF, that suggests a better neurological tolerance of this treatment.