Recurrence of abdominal pain in a peritoneal dialysis patient after treatment of peritonitis.
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Biomedical subjects
Publications and source records attributed to M Rivera.
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Chaotic synchronization of two locally coupled electrochemical oscillators is studied numerically. Both bidirectional and unidirectional couplings are considered. For both these coupling scenarios, varying the characteristics of the coupling terms (functional form and/or strength) reveals a wide variety of synchronization phenomena. Standard diagnostic tests are performed to verify and classify the different types of synchronizations observed.
The new VITEK 2 colorimetric card was compared to the previous fluorometric card for identification of yeast. API 20C was considered the "gold standard." The new card consistently performed better than the older card. Isolates from CHROMagar Candida plates were identified equally as well as those from Sabouraud dextrose agar.
BACKGROUND: Direct dialysis quantification is considered the gold standard for determining urea distribution volume, but it is impractical for routine use. So, urea distribution volume in hemodialysis patients is usually estimated from anthropometric equations. Ionic dialysance allows to calculate the urea distribution volume dividing the Kt obtained by ionic dialysance by the Kt/V obtained by a simplified formula. The aim of the present work was to analyse the concordance between the ionic dialysance and the direct dialysis quantification methods to estimate de urea distribution volume. MATERIAL AND METHODS: In 15 hemodialysis patients (10 males and 5 females), we have estimated the urea distribution volume by the direct dialysis quantification (Vurea), by the anthropometrics equations of Watson (VWatson) and Chertow (VChertow) and by the ionic dialysance method (VDI). To obtain VDI we have used two simplified Kt/V formulas: the monocompartimental and the equilibrated Daugirdas equations (VDIm and VDIe respectively). The intermethod variability was assessed by the relative difference (absolute difference between VUrea and the other methods, divided by the mean). RESULTS: VUrea (26,2 L) was statistically different from theVDIe (30,6 L, p < 0.01), VWatson 35.2 L (p < 0.001) and VChertow (38 L, p < 0.001). VDIm was 26.3 L (p = ns). VUrea represents the 42% of the body weight for the males (range 36 to 49%) and the 33% of the body weight for the female (range 28 to 38%). The intermethod variability was high for the VDIe (21.6%), VWatson (37.4%) and VChertow (48. 1%), but it was low for the VDIm (9.9%). CONCLUSIONS: Urea distribution volume calculated by the ionic dialysance method using the monocompartimental Daugirdas Kt/V equation has an acceptable agreement with the urea distribution volume calculated by the direct dialysis quantification. Anthropometry-based equations overestimate the urea distribution volume in hemodialysis patients.
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In this study, the effect of dialysate temperature on hemodynamic stability, patients' perception of dialysis discomfort and postdialysis fatigue were assessed. Thirty-one patients of the morning shift were eligible to participate in the study. Three patients refused. Patients were assessed during 6 dialysis sessions: in three sessions the dialysate temperature was normal (37 degrees C) and in other three sessions the dialysate temperature was low (35.5 degrees C). To evaluate the symptoms along the dialysis procedure and the postdialysis fatigue, specific scale questionnaires were administered in each dialysis session and respective scores were elaborated. Low temperature dialysate was associated with higher postdialysis systolic blood pressure (122 +/- 24 vs. 126 +/- 27 mmHg, p < 0.05), and lower postdialysis heart rate (82 +/- 13 vs. 78 +/- 9 beats/min, p < 0.05) with the same ultrafiltration rate. Dialysis symptoms score and postdialysis fatigue score were better with the low dialysate temperature (0.7 +/- 0.9 vs. 0.4 +/- 1 vs. p < 0.05, and 1.3 +/- 1 vs. 1 +/- 0.9 p < 0.05, respectively). Furthermore, low temperature dialysate shortened the post-dialysis fatigue period (5.4 +/- 6.3 vs. 3.1 +/- 3.3 vs. hours, p < 0.05). The clinical improvement experimented with the low temperature dialysate was not universal. A beneficial effect was exclusively observed in the patients with higher dialysis symptoms and postdialysis fatigue scores or having more than one episode of hypotension in a week. The patients were asked about their temperature preference, 7 patients (23%) request a dialysate at 37 degrees C, 19 patients (61%) prefered to be dialysed with the low temperature dialysate, and 5 patients (16%) were indifferent. The later two groups of the patients continued with the low temperature dialysate during other 4 weeks. At the end of that period, the clinical improvement remained unchanged. In summary, low temperature dialysate is particularly beneficial for highly symptomatic patients.
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A technique is presented for filtering and normalizing noisy fringe patterns, which may include closed fringes, so that single-frame demodulation schemes may be successfully applied. It is based on the construction of an adaptive filter as a linear combination of the responses of a set of isotropic bandpass filters. The space-varying coefficients are proportional to the envelope of the response of each filter, which in turn is computed by using the corresponding monogenic image [Felsberg and Sommer, IEEE Trans. Signal Process. 49, 3136 (2001)]. Some examples of demodulation of real Electronic Speckle Pattern Interferometry (ESPI) images patterns are presented.
We study the interaction of intrinsic electrochemical noise with autonomous nonlinear dynamics of a three-electrode electrochemical cell. The amplitude of this intrinsic (internal) noise, regulated by the concentration of chloride ions, is monotonically increased and the provoked dynamics is analyzed. The experimentally constructed coherence factor beta versus the concentration of the chloride ions' curve has a unimodal shape indicating the emergence of intrinsic coherence resonance. The abscissa for the maxima of this unimodal curve corresponds to the optimum value of intrinsic noise where maximum regularity of the invoked dynamics is observed.
BACKGROUND: Mesalazine as maintenance therapy in ulcerative colitis is used worldwide and has been proven to be effective. However, the optimal dosage remains to be defined. AIM: To establish whether daily treatment with 2.4 g of oral mesalazine is more effective than 1.2 g in preventing disease relapse. METHODS: A total of 156 patients with ulcerative colitis in remission were randomly treated for 1 year with 2.4 (n = 80) or 1.2 (n = 76) g/day of mesalazine. Activity of disease was assessed by periodical clinical, endoscopic and histological examinations. RESULTS: After 12 months, 24 of 80 patients (30%) on 2.4 g and 20 of 76 patients (26%) on 1.2 g were still in remission (P = N.S.). Patients in 2.4 g group remained in remission for a longer time than those in 1.2 g group (P < 0.001). Among clinical variables considered in the study, course of disease prior to enrollment (< or = 3 or > 3 relapses/year) was found to influence response to therapy. CONCLUSIONS: A daily dosage of 2.4 g of oral mesalazine seems to better at preventing and delaying relapses of ulcerative colitis than 1.2 g. The course of disease seems to be crucial in choosing the optimal dosage of mesalazine in a maintenance regimen.
Sperm motility depends on energy consumption. Low-level laser irradiation increases adenosin triphosphate (ATP) production and energy supply to the cell. The aim of this study is to analyse whether the irradiation affects the parameters that characterise dog sperm motility. Fresh dog sperm samples were divided into four groups and irradiated with a 655-nm continuous-wave diode laser with varying doses: 0 (control), 4, 6 and 10 J/cm(2). At 0, 15 and 45 min following irradiation, pictures were taken of all the groups in order to study motility with computer-aided sperm analysis (CASA). Functional tests were also performed. Average path velocity (VAP), linear coefficient (Lin) and beat cross frequency (BCF) were statistically and significantly different when compared to the control. The functional tests also showed a significant difference. At these parameters, the 655-nm continuous-wave diode laser improves the speed and linear coefficient of the sperm.
Aperiodic stochastic resonance in an electrochemical system with excitable dynamics is characterized in experiments and simulations. Two different spike trains, one with stochastic and the other with chaotic interspike intervals, are imposed on the system as subthreshold aperiodic signals. Information transmission is quantified by the cross correlation between the subthreshold input signal and the noise induced system response. A maximum is exhibited in the input-output correlation as a function of the noise amplitude. Numerical simulations with an electrochemical model are in excellent agreement with the experimental observations.
BACKGROUND: Primary antibiotic-resistance and poor compliance are the main causes of Helicobacter pylori eradication failure of standard regimens. AIM: To investigate eradication rate, patient compliance and tolerability of a 1-week once-daily levofloxacin plus azithromycin triple therapy versus the standard twice-daily triple therapy. PATIENTS AND METHODS: A total of 164 H. pylori-positive patients were randomised to either esomeprazole 20mg, levofloxacin 500 mg and azithromycin 500 mg once-daily (ELAz) or esomeprazole 20mg, clarithromycin 500 mg and amoxycillin 1g twice-daily (ECA) for 1 week. H. pylori infection was defined at entry by histology and urea breath test; cure of infection was determined both by negative urea breath test and H. pylori stool antigens. RESULTS: H. pylori eradication rates of ELAz and ECA were similar at intention-to-treat (both 65%) and per-protocol analyses (70% versus 76%, respectively). Incidence of poor compliance was lower, although not significantly, in patients randomised to ELAz than to ECA (4% versus 10%); tolerability was significantly higher for ELAz than for ECA (88% versus 70%; P=0.01). CONCLUSIONS: Once-daily levofloxacin plus azithromycin-based triple therapy achieves an H. pylori eradication rate comparable to that of standard twice-daily triple therapy, but is associated with higher patient compliance and might even be better tolerated.
INTRODUCTION: Hepatitis C virus (HCV) infection is associated with worsening disease progression after renal transplant, and to date there is no available treatment for use at this stage. It has therefore been recommended to treat HCV infection with interferon (IFN) during the dialysis period while the patient is on the waiting list for transplantation. METHODS: We analyzed data from 27 patients on hemodialysis awaiting transplant, who were under IFN treatment for chronic HCV infection (dominant genotype, 1b). The starting regime was IFN alpha-2b, 3 MU x 3/week (n = 20) or pegylated IFN alpha-2a, 135 mg/week (n = 7). If there was clearance of HCV RNA in the first 3 to 6 months, we attempted to prolong IFN treatment for 1 year, although in many patients the dose had to be reduced. A sustained response was defined as viral clearance for at least 12 months after the end of treatment. RESULTS: Viremia was negative in 13 patients (48.1%) at the end of treatment, but two of these patients relapsed, to give an overall long-term response rate of 11 patients (40.7%) and incomplete follow-up in three patients. Viral clearance was not achieved in 11 patients. In three patients (12%), IFN had to be suspended before finishing the third month of therapy due to side effects (mainly pancytopenia and intolerance of a previous kidney graft). Seven patients showing a sustained response underwent transplant, maintaining a negative viremia result. CONCLUSIONS: IFN treatment was effective in a high proportion of dialysis patients with HCV infection, with response rates possibly even higher than for the general population. However, its use is restricted by a high incidence of side effects.
We evaluated 10 patients with primary focal segmental glomerulosclerosis (FSGS) treated with plasmapheresis (PS) following renal transplantation. Three patients lost their first graft due to FSGS recurrence. In seven patients, PS was indicated as treatment for probable recurrence defined as the onset of proteinuria above 1 g/24 hours. In the remaining three patients, treatment was started in the first week posttransplant as prophylaxis against recurrence. The PS protocol was 17 sessions with the exchange of 2.5 L of plasma for 5% albumin over 10 to 12 weeks. Losartan (25 to 100 mg/d) was given to most patients at the end of PS treatment. The mean follow-up time after PS was 10 months. All patients currently have a functioning graft. A full response to treatment, defined as persistently reduced proteinuria to less than 500 mg/24 hours or the lack of recurrence in prophylactic treatment, was achieved in six patients. Three patients showed a partial decrease in proteinuria (to less than 1 g/24 hours). One patient failed to respond and still has nephrotic range proteinuria. No adverse effects of PS were recorded. A prompt start of PS combined with the use of losartan yields good results in the prophylaxis and treatment of recurrent FSGS following renal transplant in terms of quickly reduced proteinuria. Given the natural course of FSGS, a longer follow-up is needed to estimate the impact of PS on graft survival.
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Six commercial phosphates were evaluated for inhibition of the growth of 17 molds isolated from food sources. The assays were performed at neutral and natural (without pH adjustment) pH values, and the molds were streaked on plate count agar with added phosphates. Phosphate concentrations of 0.1, 0.3, 0.5, 1.0, and 1.5% (wt/vol) were used, and the MIC was determined. The resistance of molds to phosphates depended on the species. At a neutral pH, Aspergillus ochraceus and Fusarium proliferatum were resistant to all phosphates at all concentrations assayed, and Byssochlamys nivea, Aureobasidium pullulans, and Penicillium glabrum were most sensitive. The most inhibitory phosphates were those with chain lengths greater than 15 phosphate units and the highest sequestering power. At natural pH values (resulting from dissolving the phosphate in the medium), inhibitory activity changed dramatically for phosphates that produced alkaline or acidic pH in the medium. Phosphates with alkaline pH values (sodium tripolyphosphate of high solubility, sodium tripolyphosphate, and sodium neutral pyrophosphate) were much more inhibitory than phosphates at a neutral pH, but sodium acid pyrophosphate (acidic pH) had decreased inhibitory activity. The results indicate that some phosphates could be used in the food industry to inhibit molds linked to food spoilage.
Angiodysplasia is an important cause of gastrointestinal bleeding in patients with chronic renal failure. Octreotide, a long-acting synthetic somatostatin analogue that reduces splachnic blood flow have been used to treat esophageal varicose hemorrhage, but its efficacy for bleeding vascular ecstasies is awaiting support. We present three patients with chronic renal failure (two with diabetic nephropaty and the third with mesangiocapilar glomerulonephritis and hepatic cirrosis), seric creatinine 3-4,5 mg/dl, and recurrent gastrointestinal bleeding due to diffuse angiodysplasia and vascular ecstasies, diagnosed by oral endoscopy, colonoscopy and video capsule. They all were treated with octreotide, administered subcutanesly 0.1 mg twice a day for six months, with significantly decreased blood requirements in all of them, as well as the occurrence of bleeding episodes. It was well tolerated and none side-effects occurred in any subject. In our experience, octreotide is an effective and safe drug in bleeding angiodysplasia and ecstasies vascular of the gastrointestinal tract in patients with chronic renal failure, and it may be a good option especially in patients who are not candidates for surgery or endoscopic treatment due to inaccessible sites, spread of the lesion, old age and/or concomitant disorders.