Diffusion of HTO, 36Cl- and 125I- in Opalinus Clay samples from Mont Terri. Effect of confining pressure

Diffusion coefficients (T=23 +/- 2 degrees C) and accessible porosities for HTO, 36Cl(-) and 125I(-) were measured on Opalinus Clay (OPA) samples from the Mont Terri Underground Rock Laboratory (URL) using the through-diffusion technique. The direction of transport (diffusion) was perpendicular to bedding. Special cells that allowed the application of confining pressure were designed and constructed. The pressures ranged from 1 to 5 MPa, the latter value simulating the overburden at the Mont Terri URL (about 200 m). The test solution used in the experiments was a synthetic version of the Opalinus Clay pore water, which has Na(+) and Cl(-) as the main components (I=0.42 M). The measured values of the effective diffusion coefficients (D(e)) and rock capacity factors (alpha) are: D(e)=1.2-1.5 x 10(-11) m(2) s(-1) and alpha=0.09-0.11 for HTO, D(e)=4.0-5.5 x 10(-12) m(2) s(-1) and alpha=0.05 for 36Cl(-) and D(e)=3.2-4.6 x 10(-12) m(2) s(-1) and alpha=0.07-0.10 for 125I(-). For non-sorbing tracers (HTO, 36Cl) the rock capacity factor alpha is equal to the diffusion-accessible porosity epsilon. The experimental results showed that pressure only had a small effect on the value of the diffusion coefficients. Increasing the pressure from 1 to 5 MPa resulted in a decrease of the diffusion coefficient of approximately 17% for HTO, approximately 28% for 36Cl(-) and approximately 30% for 125I(-). Moreover, the diffusion coefficients for 36Cl(-) and 125I(-) are smaller than for HTO, which is consistent with an effect arising from anion exclusion. The diffusion coefficients of HTO and 125I(-) measured in this study are in good agreement with recent measurements at three other laboratories performed within the framework of a laboratory comparison exercise. The values of the diffusion-accessible porosities show a larger degree of scatter.

Modelling of nonreactive tracer dipole tests in a shear zone at the Grimsel test site

The investigation of the migration of a high pH plume in a fractured shear zone is foreseen by a long-term experiment at the Grimsel rock laboratory. In order to characterise the initial conditions for the long-term experiment and to evaluate an optimal hydraulic in situ set-up, several dipole experiments with nonreacting tracers have been performed. The dipole experiments differ in geometry, pumping rates and orientation to the background water flow. Several single and double-porosity models have been applied to fit the results of these dipole tracer tests in order to extract values for some transport parameters and discriminate for certain transport processes. A two-dimensional porous medium approach was successfully used to fit tracer breakthrough curves measured for a dipole experiment. A model based on a one-dimensional dual porous medium approach was also successful, although the applied hydraulic dipole, with similar injection and extraction rates, suggests the existence of an extended two-dimensional flow field. For the two-dimensional porous medium approach, tracer breakthrough could only be fitted with a complex flow field geometry within the heterogeneous fractured shear zone. The heterogeneity was generated by heterogeneous porosity and hydraulic permeability distributions. Predictions for further dipole geometries and a sorbing tracer have been calculated by means of both models using the flow and transport parameters deduced from fits for a single dipole experiment. This allows for comparison with the measured breakthrough of sorbing tracers. The foreseen experiment with sorbing (radionuclide) tracers will help decide on the appropriate approach that should be used to describe such dipole experiments in this shear zone. Additionally, the migration and spreading of a solution with high pH has been calculated taking into account mineral dissolution and precipitation in a two-dimensional porous medium approach in order to estimate the amount and character of the mineral reactions induced by the interaction between the high pH solution and the rock.

The effect of coupled transport phenomena in the Opalinus Clay and implications for radionuclide transport

In this study, the potential effects of coupled transport phenomena on radionuclide transport in the vicinity of a repository for vitrified high-level radioactive waste (HLW) and spent nuclear fuel (SF) hosted by the Opalinus Clay in Switzerland, at times equal to or greater than the expected lifetime of the waste canisters (about 1000 years), are addressed. The solute fluxes associated with advection, chemical diffusion, thermal and chemical osmosis, hyperfiltration and thermal diffusion have been incorporated into a simple one-dimensional transport equation. The analytical solution of this equation, with appropriate parameters. shows that thermal osmosis is the only coupled transport mechanism that could, on its own, have a strong effect on repository performance. Based on the results from the analytical model, two-dimensional finite-difference models incorporating advection and thermal osmosis, and taking conservation of fluid mass into account, have been formulated. The results show that, under the conditions in the vicinity of the repository at the time scales of interest, and due to the constraints imposed by conservation of fluid mass, the advective component of flow will oppose and cancel the thermal-osmotic component. The overall conclusion is that coupled phenomena will only have a very minor impact on radionuclide transport in the Opalinus Clay, in terms of fluid and solute fluxes, at least under the conditions prevailing at times equal to or greater than the expected lifetime of the waste canisters (about 1000 years).

Hemochromatosis gene variants in patients with cardiomyopathy

Iron depletion was suggested to be protective against the development of ischemic heart disease. Population studies have led to conflicting results, and such an association has not been addressed in patients with heart failure due to cardiomyopathy. We studied the distribution of hemochromatosis-related mutations in 319 patients with heart failure due to cardiomyopathy of different etiologies. The genotypic distribution showed a significantly higher prevalence of heterozygotes for the C282Y mutation in patients with ischemic cardiomyopathy than in patients with cardiomyopathy of nonischemic etiologies (p = 0.0036). The frequency of the D63 mutation was not significantly different between ischemic versus nonischemic groups. In multiple logistic regression models adjusted for age, sex, ethnicity, and different degrees of disease progression, there was a strong and significant association of the C282Y mutation with ischemic cardiomyopathy compared with the nonischemic group (odds ratio 6.64, 95% confidence interval 1.71 to 25.73, after adjustment). In our sample, genetic variation in the HFE gene was associated with ischemic cardiomyopathy. Such association merits further study regarding its value as a prognostic marker in patients with ischemic heart disease.

Absence of dc-conductivity in lambda-DNA

The electrical conductivity of biomaterials on a molecular scale is of fundamental interest in the life sciences. We perform first principles electronic structure calculations, which clearly indicate that lambda-DNA chains should present large resistance values. We also present two direct procedures to measure electrical currents through DNA molecules adsorbed on mica. The lower limit for the resistivity is 10(6) Omega . cm, in agreement with our calculations. We also show that low energy electron bombardment induces a rapid contamination and dramatically affects the measured conductivity, thus providing an explanation to recent reports of high DNA conductivity.

Dose-ranging study of tolterodine in patients with detrusor hyperreflexia

Tolterodine is a potent antimuscarinic agent specifically developed for the treatment of urinary urge incontinence and other symptoms related to the overactive bladder. In order to assess the optimum dosage for use in future clinical studies, a double-blind, randomized, placebo-controlled, parallel-group, multicenter study was performed in 90 patients with detrusor hyperreflexia and symptoms of urinary urgency, frequency, and/or urge incontinence. Urodynamic variables, micturition diary variables, and subjective urinary symptoms were measured before and after 2 weeks' treatment with either placebo or tolterodine 0.5, 1, 2, or 4 mg twice daily (bd). Serum drug concentrations, electrocardiogram recordings, blood pressure, and incidence of adverse events were also assessed. Linear regression analysis showed a significant dose-response relationship for several clinically relevant urodynamic variables, while there was a trend towards an improvement in micturition diary variables and subjective assessment of symptoms with increasing dosages of tolterodine. There were no safety or tolerability concerns regarding any of the dosages of tolterodine investigated, although 2 patients treated with a dosage of 4 mg bd experienced urinary retention that necessitated dosage reduction. The results of this study suggest that tolterodine is well-tolerated and exerts a dose-dependent effect on bladder function in patients with detrusor hyperreflexia. The optimum dosage of tolterodine for use in future studies is 1-2 mg bd.

Is there a place for pudendal nerve maximal electrical stimulation for the treatment of detrusor hyperreflexia in spinal cord injury patients?

The aim of the study is to determine whether pudendal nerve maximal electrical stimulation (MES) could represent an alternative treatment for detrusor hyperreflexia in spinal cord injury (SCI) patients. Six suprasacral SCI patients participated in the study. The treatment consisted of daily stimulation periods of 20 min, repeated five times a week, during 4 weeks, with continuous electrical stimulation of the penis or of the clitoris via bipolar surface electrodes (rectangular stimuli of 0.5 ms pulse duration, 5 Hz frequency), with the maximum tolerable stimulation strength (under the level of pain). In two patients, additional stimulation was administrated by means of an anal plug during the last 2 weeks. The stimulus strengths ranged from 35 to 99 mA (mean 54 mA). One patient stopped MES after 2 weeks. At the end of the treatment, neither the cystometric bladder capacities (153 ml vs 157 ml) nor the micturition charts had significantly improved for the five remaining patients. Only two patients experienced non lasting improvement of nocturia at some time of the treatment. In conclusion, we were not able to demonstrate the efficacy of MES in inhibiting detrusor hyperreflexia in SCI patients. To reach therapeutic effects, other parameters may be needed, such as higher stimulation strengths (currents above or equal to 99 mA) or other currents (such as interferential therapy). Chronic stimulation with external or implanted electrodes using lower currents may represent an alternative.

Special characteristics of osteoid osteoma in the proximal phalanx

We report two cases of osteoid osteoma in the proximal phalanx. This is an uncommon location for the lesion and it has special clinical and radiological features. Both cases were successfully treated when an 'en bloc' excision of the lesion, including the nidus, was performed. Four operations were required in the first case.

Ovarian follicular dynamics in nelore breed () cattle

The most common beef cattle raised in Brazil is the Nelore breed (Bos indicus). Information obtained by ultrasonography on follicular growth in Bos taurus cattle has been accumulating rapidly. However, there are few publications to date on follicular development in Bos indicus breeds. The follicular dynamics in Nelore heifers and cows during natural or prostaglandin (PG)-induced estrous cycle were studied. From the detection of estrus onward, all animals were examined daily by ultrasonography for one (n = 35) or two (n = 10) consecutive estrous cycles. The follicular dynamic in Nelore cattle was characterized by the predominance of 2 follicular waves in the cows (83.3%, n = 18, P < 0.05) and 3 waves in the heifers (64.7%, n = 16, P < 0.05). Most of the cattle observed over 2 consecutive estrous cycles presented the same pattern of follicular waves in the first and second cycle, and only 30% showed variation in the number of waves from one cycle to the other. Most of the follicular parameters analyzed were not affected by PG treatment or age but were altered by follicular waves. Consequently, data on cows and heifers were combined according to the number of follicular waves. The ovulatory follicle was larger than the other dominant follicles (P < 0.05), and the ovulatory wave was shorter than the preceding waves (P < 0.05). The interovulatory interval was longer in animals showing 3 waves than those exhibiting 2 waves (P < 0.05). Maximum diameter of the dominant follicle (around 11 mm) and of the corpus luteum (CL, approximately 17 mm) were smaller than those reported for European breeds. In conclusion, the results demonstrate that although the dominant follicle and corpus luteum are smaller than in European breeds, the follicular dynamics in Nelore cattle were similar to those observed in European breeds and were characterized by 2 or 3 follicular waves for cows and heifers, respectively, during the natural or prostaglandin-induced estrous cycle.

Medial rotational tibial osteotomy for patellar instability secondary to lateral tibial torsion

We report 35 medial rotational osteotomies in 25 patients with chronic disability suggesting patello-femoral subluxation secondary to lateral tibial torsion. None had responded to conservative measures or soft tissue operations. The osteotomy was transverse in 17 and oblique in 18. The follow up averaged 4.3 years (range 1 to 8 years). The alignment of the limb was assessed clinically, and by radiographs and CT scans. The results were good or excellent in 88.5%, fair in 5.7% and poor in 5.7%. Twenty-three patients were satisfied and 2 were not. The overall results have been satisfactory in athletes and those leading an active life.

Short-term effect of pudendal nerve electrical stimulation on detrusor hyperreflexia in spinal cord injury patients: importance of current strength

Twenty patients with chronic suprasacral spinal cord injury presenting with detrusor hyperreflexia were examined. In a preliminary study in ten patients we investigated the reproducibility of bladder capacity through the repetition of three cystometries. The effect of electrical stimulation (ES) on detrusor hyperreflexia was then investigated in ten patients during three consecutive cystometries, the first one without ES (baseline) and the other two with continuous ES of the dorsal penile or clitoris nerve via surface electrodes. Parameters of stimulation were 5 Hz frequency, 0.50 msec pulse duration, and stimulation strength of 1 and 2 times the bulbocavernosus reflex threshold. No significant differences in bladder capacity were found between the three consecutive cystometries without ES (respectively 97.0 ml, 101.5 ml and 105.6 ml). A current at the bulbocavernosus threshold (mean 24.4 mA) failed to induce a significant increase in bladder capacity compared to baseline (173.0 ml vs 155.5 ml, P = 0.17) whereas a current of twice the bulbocavernosus threshold (mean 48.9 mA) was highly significant (318.5 ml vs 155.5 ml, P < 0.007). ES of twice the threshold resulted in perineal contraction in all of the patients, the threshold ES never did. Our results emphasise the decisive roles of perineal contraction and of current strength for achieving short-term bladder inhibition in spinal cord injury patients. The carry-over effect may also be dependent on the current strength. If so, maximal pudendal ES could represent an alternative procedure in the treatment of detrusor hyperreflexia in these patients.

Pseudotumoral articular amyloidosis

We present a 71-year-old man with primary amyloidosis characterized by several outstanding clinical features, namely hip involvement of a pseudotumoral appearance, periarticular osteolytic lesions and a pathological fracture. Kappa light chains in the synovial fluid were observed. The patient survived for 90 months without developing plasma cell dyscrasia, and with preservation of vital functions despite parenchymal involvement of multiple organs.

Propofol vs midazolam in short-, medium-, and long-term sedation of critically ill patients. A cost-benefit analysis

The purpose of this study was to evaluate and compare the clinical effects, safety, and economic cost of propofol and midazolam in the sedation of patients undergoing mechanical ventilation in the ICU. Eighty-eight critically ill patients were studied and randomly allocated to receive short-term (less than 24 h), medium-term (24 h to 7 days), and prolonged (more than 7 days) continuous sedation with propofol (n = 46) or midazolam (n = 42). Mean doses required were 2.36 mg/kg/h for propofol and 0.17 mg/kg/h for midazolam. Patients in the group receiving propofol showed a percentage of hours of sedation at the desired level (grade 2, 3, 4, or 5 on the Ramsay scale) of 93 percent, compared with 82 percent (p < 0.05) in the group receiving midazolam. Both agents were considered safe with respect to the induction of adverse reactions during their use in prolonged sedation. Recovery after interrupting sedation was significantly faster in patients treated with propofol than in those sedated with midazolam (p < 0.05). Recovery of total consciousness was predictable according to sedation time in propofol-treated subgroups (r = 0.98, 0.88, and 0.92, respectively), while this correlation was not observed in the midazolam-treated group. In the subgroup with sedation of less than 24 h, propofol provided a cost savings of approximately 2,000 pesetas (pts) per patient, due to shorter stays in the ICU. We conclude that propofol is a sedative agent with the same safety, higher clinical effectiveness, and a better cost-benefit ratio than midazolam in the continuous sedation of critically ill patients.

[Plea for interactive rehabilitation during coma]

The question of head trauma reasons, and the shock of traditional family and therapeutic references, make the authors examine clinic coma evolution till awakening. From signs of libidinal values collected by care-team, another way during coma and till life recovery, is rebuilt.