Intensifying renal replacement therapy during pregnancy: the role for nocturnal home hemodialysis

Fertility among women receiving conventional hemodialysis or peritoneal dialysis is very low. For those able to conceive it appears that infant survival is poor, and prematurity and its related complications are still commonplace. Nocturnal hemodialysis (NHD) is a form of intensive, self-administered hemodialysis whereby patients receive 3–4 times the duration of conventional hemodialysis resulting in superior removal of uremic toxins compared to traditional dialysis modalities. NHD has been associated with increased fertility, infants with higher birth weights born at more advanced gestational ages, and fewer maternal and fetal complications. These encouraging results suggest a greater role for much more intensive dialysis in pregnancy.     

Magnetoencephalography is more successful for screening and localizing frontal lobe epilepsy than electroencephalography

PURPOSE: The diagnosis of frontal lobe epilepsy may be compounded by poor electroclinical localization, due to distributed or rapidly propagating epileptiform activity. This study aimed at developing optimal procedures for localizing interictal epileptiform discharges (IEDs) of patients with localization related epilepsy in the frontal lobe. To this end the localization results obtained for magnetoencephalography (MEG) and electroencephalography (EEG) were compared systematically using automated analysis procedures. METHODS: Simultaneous recording of interictal EEG and MEG was successful for 18 out of the 24 patients studied. Visual inspection of these recordings revealed IEDs with varying morphology and topography. Cluster analysis was used to classify these discharges on the basis of their spatial distribution followed by equivalent dipole analysis of the cluster averages. The locations of the equivalent dipoles were compared with the location of the epileptogenic lesions of the patient or, if these were not visible at MRI with the location of the interictal onset zones identified by subdural electroencephalography. RESULTS: Generally IEDs were more abundantly in MEG than in the EEG recordings. Furthermore, the duration of the MEG spikes, measured from the onset till the spike maximum, was in most patients shorter than the EEG spikes. In most patients, distinct spike subpopulations were found with clearly different topographical field maps. Cluster analysis of MEG spikes followed by dipole localization was successful (n = 14) for twice as many patients as for EEG source analysis (n = 7), indicating that the localizability of interictal MEG is much better than of interictal EEG. CONCLUSIONS: The automated procedures developed in this study provide a fast screening method for identifying the distinct categories of spikes and the brain areas responsible for these spikes. The results show that MEG spike yield and localization is superior compared with EEG. This finding is of importance for the diagnosis and preoperative evaluation of patients with frontal lobe epilepsy.     

Gender differences in the cognitive control of emotion: An fMRI study

The interaction of emotion and cognition has become a topic of major interest. However, the influence of gender on the interplay between the two processes, along with its neural correlates have not been fully analysed so far. In this functional magnetic resonance imaging (fMRI) study we induced negative emotion using negative olfactory stimulation while male (n=21) and female (n=19) participants performed an n-back verbal working memory task. Based on findings indicating increased emotional reactivity in women, we expected the female participants to exhibit stronger activation in characteristically emotion-associated areas during the interaction of emotional and cognitive processing in comparison to the male participants. Both groups were found to be significantly impaired in their working memory performance by negative emotion induction. However, fMRI analysis revealed distinct differences in neuronal activation between groups. In men, cognitive performance under negative emotion induction was associated with extended activation patterns in mainly prefrontal and superior parietal regions. In women, the interaction between emotion and working memory yielded a significantly stronger response in the amygdala and the orbitofrontal cortex (OFC) compared to their male counterparts. Our data suggest that in women the interaction of verbal working memory and negative emotion is associated with relative hyperactivation in more emotion-associated areas whereas in men regions commonly regarded as important for cognition and cognitive control are activated. These results provide new insights in gender-specific cerebral mechanisms.     

Peginterferon alfa-2b and weight-based or flat-dose ribavirin in chronic hepatitis C patients: a randomized trial

This prospective, multicenter, community-based and academic-based, open-label, investigator-initiated, U.S. study evaluated efficacy and safety of pegylated interferon (PEG-IFN) alfa-2b plus a flat or weight-based dose of ribavirin (RBV) in adults with chronic hepatitis C. Patients (n = 5027) were randomly assigned to receive PEG-IFN alfa-2b 1.5 microg/kg/week plus flat-dose (800 mg/day) or weight-based (800-1400 mg/day) RBV for 48 weeks (patients with genotype 1, 4, 5, or 6) and for 24 or 48 weeks (genotype 2/3 patients). Primary end point was sustained virologic response (undetectable [<125 IU/mL] serum hepatitis C virus RNA at 24-week follow-up). Sustained virologic response, but not end-of-treatment, rates were significantly higher with weight-based than with flat-dose RBV (44.2% versus 40.5%; P = 0.008). Sustained virologic response rates by intention-to-treat analysis were 34.0% and 28.9%, respectively, in genotype 1 patients (P = 0.005) and 31.2% and 26.7%, respectively, in genotype 1 patients with high baseline viral load (P = 0.056). In genotype 2/3 patients, rates were not significantly different (61.8% and 59.5%, respectively) regardless of treatment duration. Besides greater hemoglobin reductions with weight-based RBV, safety profiles were similar across RBV dosing groups, including the 1400-mg/day group. CONCLUSION: PEG-IFN alfa-2b plus weight-based RBV is more effective than flat-dose RBV, particularly in genotype 1 patients, providing equivalent efficacy across all weight groups. RBV 1400 mg/day is appropriate for patients 105 to 125 kg. For genotype 2/3 patients, 24 weeks of treatment with flat-dose RBV is adequate; no evidence of additional benefit of extending treatment to 48 weeks was demonstrated.     

Arterial-wave reflections are increased in heart failure patients with a left-ventricular assist device

BACKGROUND: Chronic heart failure (HF) is associated with increased central arterial pulse-wave reflections, which may contribute to increased myocardial oxygen demand. Although the treatment of HF via left-ventricular assist device (LVAD) placement has recently become widespread, the effects of LVAD therapy on central arterial pulse-wave reflections are unknown. METHODS: Central aortic pulse-wave analysis was performed on patients with end-stage HF awaiting cardiac transplantation and on healthy age-matched controls using the SphygmoCor (Akor Medical, Sydney, Australia) system. Arterial pulse-wave data were compared between patients receiving LVAD support versus those receiving intravenous inotropic drugs and healthy control patients. RESULTS: Five patients on LVAD support were compared with 10 patients on inotropic drugs and 10 healthy control patients. Aortic augmented pressure and the aortic augmentation index (AI(a)) were higher in LVAD patients compared with inotrope and control patients, despite similar brachial and aortic blood pressures between groups. The AI(a) was significantly higher in LVAD patients than in patients on inotropic drugs (28.2% +/- 10% v 7.9% +/- 9%, P < or = .01). Additionally, there was a significantly higher aortic systolic tension time index, an index of left-ventricular myocardial oxygen demand, in the LVAD group compared with the inotrope group (2655 +/- 298 mm Hg/sec/min v 1748 +/- 303 mm Hg/sec/min, P < .01). CONCLUSIONS: Central arterial pressure-wave reflection is increased in end-stage HF patients on LVAD support compared with those on inotropic drugs, leading to an increase in aortic augmented pressure, AI(a), and systolic tension time index. The AI(a) is also higher in LVAD patients than in healthy controls. This increased central arterial-wave reflection places an additional hemodynamic load on the LVAD device and may have relevance to the medical management of patients after LVAD placement and to the longevity of the LVAD device itself.     

Quantitative evaluation of the relaxivity effects of iodine on GD-DTPA enhanced MR arthrography

PURPOSE: To quantify the effect of iodine on the gadolinium (Gd) contrast-enhanced signal in MR arthrography. MATERIALS AND METHODS: Saline solutions of Gd contrast agent (0-1 mmol/liter) were mixed with iodinated contrast agent (0-185 mmol/liter). The T1 and T2 relaxation constants of these solutions were measured at 1.5T. Different types of commonly used iodinated contrast agents as well as sodium iodide (NaI) solutions were also analyzed. RESULTS: Iodine caused significant T2 shortening and some T1 shortening in Gd contrast solutions. Both contrast agents independently obeyed the standard relaxation relation, and their mixture obeyed a modified version of this relation. The side chains in various iodine molecules and their viscosities affected the relaxation properties differently. For various spin-echo (SE) sequences, the signal from synovial fluid containing different concentrations of the two contrast agents was calculated. The T2-weighted signal appeared to be most affected by the increase in iodine concentrations. In the absence of Gd contrast, all SE sequences showed an initial increase in signal from iodine contrast. CONCLUSION: A generalized relation for the relaxivities of Gd contrast in the presence of iodine was established. The side chains of iodine contrast were found to alter the relaxivities of Gd contrast. Imaging with proton density (PD)-weighted SE with only iodine contrast agent was found to be feasible.     

Methodological considerations for research in nocturnal home hemodialysis

Nocturnal hemodialysis (NHD) is a form of frequent, intensive renal replacement therapy, which has been suggested to offer multiple physiological benefits over conventional hemodialysis (CHD). Though the evidence supporting these advantages is steadily increasing, significant methodological challenges exist in conducting research in this area. Our review highlights these important considerations and potential biases within the present NHD literature and suggests future research opportunities.