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Biomedical subjects

Ricardo Correa-Rotter

Publications and source records attributed to Ricardo Correa-Rotter.

At least 19 recordsLinked to original sources

Screening for tuberculosis in the study of the living renal donor in a developing country.

Given the high prevalence of tuberculosis (Tb) in the Mexican population, a strict program to detect Tb in the potential donor is required. Chest x-ray, excretory urogram, urinalysis with microscopic exam of the sediment, urine cultures for M. tuberculosis, and tuberculin skin test (TST) with PPD-RT23 performed for evaluation of 222 living donors were reviewed. Isoniazid prophylaxis before kidney donation was gathered. Donors and recipients were followed up for a minimum of 2 years. According to the TST result, 36.8% of the donors had latent tuberculosis; however, all other studies were normal or negative in all of them. Use of isoniazid prophylaxis in TST-positive donors made no difference in risk of transmission of tuberculosis to the recipient or development of tuberculosis among the donors. Normal chest x-ray and excretory urogram, along with a negative microscopic examination of the urine, safely exclude tuberculosis transmission to recipients.

Adolescent↗

Prevention strategies for chronic kidney disease in Latin America: a strategy for the next decade--a report on the Villarica Conference.

Representatives from 19 Latin American countries gathered to report and deliberate on both the present and future implications of the growing epidemic of chronic kidney disease-as well as cardiovascular disease, diabetes, and hypertension-and to define the role that national health systems need to adopt in order to cope with them. Country-by-country reports provided an excellent overview of the current state of health care in general and chronic diseases in particular. The meeting concluded with a consensus statement on the most urgent needs for the next decade.

Awareness↗

Markers of inflammation before and after renal transplantation.

BACKGROUND: This study aims to compare serum C-reactive protein (CRP), interleukin (IL-6), and tumor necrosis factor (TNF)-alpha in end-stage renal disease (ESRD) patients before versus after receiving renal transplantation (RT) and versus donors. METHODS: Serum samples from 37 ESRD patients (24 male, age 34+/-13 years) were collected before and after RT; in addition, samples from 31 donors were obtained at transplantation. CRP concentrations were measured using nephelometry, and TNF-alpha and IL-6 were measured by enzyme-linked immunoadsorbent assay. RESULTS: Ninety-two percent of recipients had a living donor, 73% received cyclosporine A, 27% tacrolimus, and 70% induction with daclizumab. Thirteen percent had acute rejection and 16% chronic allograft nephropathy. All inflammation markers decreased 6 months after RT, but only CRP was below baseline values (baseline: 5.0+/-3.5; 6 months: 3.0+/-0; 12 months: 3.2+/-0.7; 18 months: 3.2+/-0.6; donors: 3.6+/-1.5 mg/L; P<0.05), whereas median TNF-alpha (baseline: 0.1 [0.03-0.2]; 6 months: 0 [0-0.1]; 12 months: 0.3 [0.1-2.6]; 18 months: 0.6 [0.1-1.9]; donors: 0 [0-0.1] pg/mL; P<0.05) and IL-6 (baseline: 1.9 [1.2-7.1]; 6 months: 1.2 [0.6-28.3]; 12 months: 2.6 [1.3-3.4]; 18 months: 2.7 [1.7-4.2]; donors: 1.1 [0.6-1.9] pg/mL; P<0.05) significantly increased up to the end of follow-up. Before RT, CRP correlated with age (r 0.45, P=0.006) and albumin (r -0.36, P=0.04). TNF-alpha and IL-6 were correlated before (r 0.34, P=0.04) and after (r 0.55, P=0.02) RT. Inflammation markers were not different in patients who had acute rejection episodes or chronic nephropathy. CONCLUSIONS: Compared with controls, patients displayed an inflammatory phenomenon before receiving RT. Serum CRP decreased significantly after RT, whereas TNFalpha and IL-6 increased.

Adult↗

Differential effects of teriparatide and alendronate on bone remodeling in postmenopausal women assessed by histomorphometric parameters.

UNLABELLED: An 18-month randomized double-blind study was conducted in postmenopausal women with osteoporosis to compare the effects of once-daily teriparatide 20 microg with alendronate 10 mg on bone histomorphometry. Biopsies were obtained from 42 patients. Indices of bone formation were significantly higher after 6 or 18 months of teriparatide compared with alendronate treatment. INTRODUCTION: Alendronate and teriparatide increased BMD, assessed by DXA, by different mechanisms of action, supported by changes in biochemical markers of bone turnover. The purpose of this cross-sectional study was to explore the differential effects of these two osteoporosis treatments at the bone tissue level by examining bone histomorphometric parameters of bone turnover after either 6 or 18 months of treatment. MATERIALS AND METHODS: Patients were a cohort from a randomized parallel double-blind study conducted to compare the effects of once-daily teriparatide 20 microg and alendronate 10 mg in postmenopausal women with osteoporosis. Transiliac crest bone biopsies were obtained after tetracycline double labeling from 42 patients treated for 6 months (n = 23) or 18 months (n = 14); 5 additional patients were biopsied from contralateral sides at 6 and 18 months. Biopsy specimens adequate for quantitative analysis were analyzed by 2D histomorphometry from 17 patients at 6 months (teriparatide, n = 8; alendronate, n = 9) and 15 patients at 18 months (teriparatide, n = 8; alendronate, n = 7). Data were analyzed by two-sample tests. RESULTS: Histomorphometric indices of bone formation were significantly and markedly greater in the teriparatide group than in the alendronate group at 6 and 18 months, whereas indices of bone resorption were only significantly greater in the teriparatide group than in the alendronate group at 6 months. Bone formation and activation frequency were significantly lower at 18 months compared with 6 months in the teriparatide group, returning to levels comparable with untreated postmenopausal women. In the teriparatide group, the peak in histomorphometric bone formation indices coincided with peak levels for N-terminal propeptide of type I collagen, a biochemical marker of bone formation. The degree of mineralization was lower at 18 months than at 6 months with treatment in both groups but was not different between groups. CONCLUSIONS: These results confirm the opposite mechanisms of action of teriparatide and alendronate on bone remodeling and confirm the bone formation effect of teriparatide.

Absorptiometry, Photon↗

Prevention of chronic kidney and vascular disease: toward global health equity--the Bellagio 2004 Declaration.

Chronic kidney disease (CKD) not only reflects target organ injury in systemic vascular disease in the general population and in association with diabetes, hypertension, and smoking, but it is recognized as one of the major risk factors in the pathogenesis and outcome of cardiovascular disease. Recent surveys have revealed that the prevalence of CKD, particularly the hidden mild form (mildly elevated levels of serum creatinine or urinary albumin excretion), is surprisingly high in the general population. In recent years, the global epidemic of type 2 diabetes has led to an alarming increase in the number of patients with CKD. Most patients with CKD (over 50 million individuals worldwide) succumb to cardiovascular events, while each year over 1 million develop end-stage renal failure, which requires costly treatment and in many countries of the world, unaffordable renal replacement therapy by chronic dialysis or renal transplantation. Alarmed by the immense challenge to human morbidity and the economic burden of CKD and ensuing systemic cardiovascular disease, the International Society of Nephrology convened a multidisciplinary group of expert physicians and public health leaders from around the world to develop strategies to delay and avert this bleak future by effective prevention of CKD based on awareness, early detection, and effective treatment.

Cardiovascular Diseases↗

Early detection and prevention of diabetic nephropathy: a challenge calling for mandatory action for Mexico and the developing world.

During the last decades, developing countries have experienced an epidemiologic transition characterized by a reduction of infectious diseases and an increase of chronic degenerative diseases. This situation is generating tormenting public health, financial, and social consequences. Of particular relevance is type 2 diabetes mellitus and its chronic complications, particularly cardiovascular disease and diabetic nephropathy, because mortality of the patient with diabetes is, in most instances, related to these complications. There is a clear need to implement diagnostic and treatment strategies to reduce risk factors for development of diabetes (primary prevention), to detect risk factors of chronic complications in early stages of diabetes (secondary prevention), and to prevent further progression of those that already have renal injury (tertiary prevention). Microalbuminuria is an early marker of renal injury in diabetes, and its early detection can help the timely use of renal preventive measures, which would avoid the extremely high costs of renal replacement treatment for end-stage renal disease as well as that of other cardiovascular complications. Preventive strategies are of very little or no impact, if the primary physician has limited knowledge about the natural history of diabetic nephropathy, the beneficial effect of early preventive maneuvers for delaying its progression, and the social and economic impact of end-stage renal disease. It is therefore imperative to assure in our health systems that general practitioners have the ability and commitment to detect early diabetes complications, in order to promote actions that support regression or retard highly morbid cardiovascular and renal conditions.

Adolescent↗

Soy protein diet ameliorates renal nitrotyrosine formation and chronic nephropathy induced by puromycin aminonucleoside.

It has been shown that reactive oxygen species are involved in chronic puromycin aminonucleoside (PAN) induced nephrotic syndrome (NS) and that a 20% soy protein diet reduces renal damage in this experimental model. The purpose of the present work was to investigate if a 20% soy protein diet is able to modulate kidney nitrotyrosine formation and the activity of renal antioxidant enzymes (catalase, glutathione peroxidase, Cu,Zn- or Mn-superoxide dismutase) which could explain, at least in part, the protective effect of the soy protein diet in rats with chronic NS induced by PAN. Four groups of rats were studied: (1) Control rats fed 20% casein diet, (2) Nephrotic rats fed 20% casein diet, (3) Control rats fed 20% soy protein diet, and (4) Nephrotic rats fed 20% soy protein diet. Chronic NS was induced by repeated injections of PAN and rats were sacrificed at week nine. The soy protein diet ameliorated proteinuria, hypercholesterolemia, and the increase in serum creatinine and blood urea nitrogen observed in nephrotic rats fed 20% casein diet. Kidney nitrotyrosine formation increased in nephrotic rats fed 20% casein diet and this increase was ameliorated in nephrotic rats fed 20% soy protein diet. However, the soy protein diet was unable to modulate the antioxidant enzymes activities in control and nephrotic rats fed 20% soy protein diet. Food intake was similar in the two diet groups. The protective effect of a 20% soy protein diet on renal damage in chronic nephropathy induced by PAN was associated with the amelioration in the renal nitrotyrosine formation but not with the modulation of antioxidant enzymes.

Animals↗

In vivo IL-10 and TGF-beta production by PBMC from long-term kidney transplant recipients with excellent graft function: a possible feedback mechanism participating in immunological stability.

BACKGROUND: Interleukin-10 (IL-10) and transforming growth factor-beta (TGF-beta) are Th2-derived multifunctional cytokines that exhibit potent immunoregulatory and anti-inflammatory properties which might prolong graft survival. The aim of this study was to explore whether spontaneous production of IL-10 and TGF-beta by blood mononuclear cells correlates with excellent long-term graft function. METHODS: A cross-sectional study was carried out in 32 kidney transplant recipients, without albuminuria, treated with azathioprine and prednisone. Spontaneous IL-10 and TGF-beta were measured by enzyme-linked immunosorbent assay in supernatants from 24 h cultured unstimulated peripheral blood mononuclear cells. Both cytokines were also determined in 10 healthy kidney donors. RESULTS: There was no correlation between IL-10 or TGF-beta with any variable tested, namely age, SCr, histocompatibility, and post-transplant follow-up. In vivo IL-10 production displayed a statistical trend to be higher in transplant recipients than in controls (362.3 +/- 465, range 12.5-1929.3 pg/ml, and 189 +/- 170, range 4.17-485.7 pg/ml, respectively; p = 0.08), whereas no difference was observed in TGF-beta among the same groups (134.7 +/- 79.2, range 68-421 pg/ml, and 121.4 +/- 25.8, range 75-151 pg/ml, respectively). Interestingly, a statistically significant inverse correlation was observed between IL-10 and TGF-beta in kidney transplant recipients (p = 0.03). CONCLUSIONS: The higher IL-10 production observed in long-term kidney transplant recipients supports the notion that this cytokine contributes in decreasing allogenic immune responses and allows prolongation of allograft survival. The balance between TGF-beta and IL-10 may be of paramount importance in graft acceptance.

Adult↗

Demographic and epidemiologic transition in the developing world: role of albuminuria in the early diagnosis and prevention of renal and cardiovascular disease.

The developing world is facing a real pandemic of renal and cardiovascular disease. With the decrease of infectious disease morbidity and mortality, and the exposure to more westernized life style, signs of increasing renal and cardiovascular disease is particularly shown in the tremendous rise in type 2 diabetes and its sequelae. A group of doctors and scientists from all over the world have convened in Bellagio to halt this dramatic disease change and burden to the developing countries. They came to the conclusion that screening and treatment should clearly focus on cost-beneficial strategies, among which blood pressure and urinary albumin measurement, as well as effective and affordable treatment strategies to lower blood pressure and albuminuria, are essential.

Albuminuria↗

Prevalence of hepatitis C virus infection among hemodialysis patients at a tertiary-care hospital in Mexico City, Mexico.

We determined the prevalence of hepatitis C virus (HCV) in hemodialysis patients by antibody testing and HCV RNA determination by PCR. A total of 149 patients with kidney failure with replacement therapy were tested. The prevalence of anti-HCV was 6.7% (10 of 149 patients), and viremia was detectable in 8 of 149 (5%) patients. Three of 149 patients (2%) were anti-HCV negative with detectable HCV RNA.

Hepatitis C↗

Association of vitamin D receptor polymorphisms with osteoporosis in mexican postmenopausal women.

It has been reported that Vitamin D receptor polymorphisms are associated with osteoporosis, particularly those demonstrated by the BsmI and FokI restriction enzymes. Herein we report the results of a case-control study performed in postmenopausal Mexican women. We studied 65 osteoporotic women (< or = -2.5 SD bone mineral density [BMD] of young normal females) and 57 controls (over 90% > or = -1.5 SD BMD of young normal females. Restriction enzymes BsmI and FokI were used to identify polymorphisms. Odds ratios and their 95% confidence intervals were calculated, and analysis was performed controlling for age as a covariate. The BsmI genotypes revealed a higher frequency of the bb genotype in cases than in controls, contradicting much of the literature that suggests this genotype protects females against osteoporosis. Regarding the FokI genotypes, we were unable to confirm that the FF genotype has a protective effect against osteoporosis. The inconsistencies found in the literature and the results obtained in the present work suggest to us that other genetic and nongenetic factors are involved in the occurrence of osteoporosis, confounding the results of the possible association of osteoporosis and VDR polymorphisms.

Aged↗

Genetic factors play an important role in the pathogenesis of hyperlipidemia post-transplantation.

BACKGROUND: Our purpose was to identify factors associated with hyperlipidemia post-transplantation in a Hispanic population. METHODS: From 1985 to 1999, a kidney graft survival longer than 3 months occurred in 293 cases at the Instituto Nacional de la Nutrición. Most of the patients living in Mexico City were included (n = 83). The evaluation included a questionnaire, blood samples, and assessment of body composition and dietary habits. As many as possible first-degree relatives were studied. RESULTS: Women had higher values of cholesterol (236 +/- 51 versus 215 +/-41; P < 0.05), low-density lipoprotein cholesterol (147 +/- 42 versus 131 +/- 34; P = 0.05), high-density lipoprotein cholesterol (57.3 +/- 14 versus 47.9 +/- 14; P = 0.002) and high-density lipoprotein-2 cholesterol. Isolated hypercholesterolemia was the most common lipid abnormality (40.9%), followed by mixed hyperlipidemia. Lipoprotein (a) greater than 30 mg/dL was found in 13 cases. Familial combined hyperlipidemia (FCHL) in the patient's relatives was a marker for dyslipidemia (odds ratio, 7.04; 95% confidence interval, 1.2 to 59.7). These cases had a worse lipid profile. Cyclosporine-treated FCHL patients had higher lipid levels compared with the non-FCHL, cyclosporine-treated patients. The effects of cyclosporine on the lipid levels were lower, but significant, after the exclusion of the FCHL cases. CONCLUSION: Post-transplant dyslipidemia is determined by genetic and environmental factors. FCHL in the patient's relatives was associated with post-transplant hyperlipidemia; an additive effect with cyclosporine was found. The evaluation of the lipid profile of relatives may be useful for the assessment of the risk of post-transplant dyslipidemia.

Adult↗

A soy protein diet alters hepatic lipid metabolism gene expression and reduces serum lipids and renal fibrogenic cytokines in rats with chronic nephrotic syndrome.

Nephrotic syndrome (NS) is characterized by the presence of proteinuria and hyperlipidemia. However, ingestion of soy protein has a hypolipidemic effect. The present study was designed to determine whether the ingestion of a 20% soy protein diet regulates the expression of hepatic sterol regulatory element binding protein (SREBP)-1, fatty acid synthase (FAS), malic enzyme, beta-hydroxy-beta-methylglutaryl-CoA (HMG-CoA) reductase (r) and synthase (s), and LDL receptor (r), and to assess whether soy protein improves lipid and renal abnormalities in rats with chronic NS. Male Wistar rats were injected with vehicle or with puromycin aminonucleoside to induce NS and were fed either 20% casein or soy protein diets for 64 d. NS rats fed 20% soy protein had improved creatinine clearance and reduced proteinuria, hypercholesterolemia, hypertriglyceridemia, as well as VLDL-triglycerides and LDL cholesterol compared with NS rats fed the 20% casein diet. In addition, the soy protein diet decreased the incidence of glomerular sclerosis, and proinflammatory cytokines in kidney. Ingestion of the soy protein diet by control rats reduced the gene expression of SREBP-1, malic enzyme, FAS and increased HMG-CoAr, HMG-CoAs and LDLr. However, NS rats fed either casein or soy protein diets had low insulin concentrations with reductions in SREBP-1, FAS and malic enzyme expression compared with control rats fed the casein diet. NS rats fed the soy diet also had lower HMG-CoAr and LDLr mRNA levels than NS rats fed casein. In conclusion, the beneficial effects of soy protein on lipid metabolism are modulated in part by SREBP-1. However, in NS rats, the benefit may be through a direct effect of this protein on kidney rather than mediated by changes in expression of hepatic lipid metabolism genes.

Animals↗

A randomized double-blind trial to compare the efficacy of teriparatide [recombinant human parathyroid hormone (1-34)] with alendronate in postmenopausal women with osteoporosis.

Teriparatide (rDNA origin) injection [recombinant human PTH (1-34)] stimulates bone formation, increases bone mineral density (BMD), and restores bone architecture and integrity. In contrast, bisphosphonates reduce bone resorption and increase BMD. We compared the effects of teriparatide and alendronate sodium on BMD, nonvertebral fracture incidence, and bone turnover in 146 postmenopausal women with osteoporosis. Women were randomized to either once-daily sc injections of teriparatide 40 micro g plus oral placebo (n = 73) or oral alendronate 10 mg plus placebo injection (n = 73). Median duration of treatment was 14 months. At 3 months, teriparatide increased lumbar spine BMD significantly more than did alendronate (P < 0.001). Lumbar spine-BMD increased by 12.2% in the teriparatide group and 5.6% in the alendronate group (P < 0.001 teriparatide vs. alendronate). Teriparatide increased femoral neck BMD and total body bone mineral significantly more than did alendronate, but BMD at the one third distal radius decreased, compared with alendronate (P < or = 0.05). Nonvertebral fracture incidence was significantly lower in the teriparatide group than in the alendronate group (P < 0.05). Both treatments were well tolerated despite transient mild asymptomatic hypercalcemia with teriparatide treatment. In conclusion, teriparatide, a bone formation agent, increased BMD at most sites and decreased nonvertebral fractures more than alendronate.

Adult↗

Effects of increased peritoneal clearances on mortality rates in peritoneal dialysis: ADEMEX, a prospective, randomized, controlled trial.

Small-solute clearance targets for peritoneal dialysis (PD) have been based on the tacit assumption that peritoneal and renal clearances are equivalent and therefore additive. Although several studies have established that patient survival is directly correlated with renal clearances, there have been no randomized, controlled, interventional trials examining the effects of increases in peritoneal small-solute clearances on patient survival. A prospective, randomized, controlled, clinical trial was performed to study the effects of increased peritoneal small-solute clearances on clinical outcomes among patients with end-stage renal disease who were being treated with PD. A total of 965 subjects were randomly assigned to the intervention or control group (in a 1:1 ratio). Subjects in the control group continued to receive their preexisting PD prescriptions, which consisted of four daily exchanges with 2 L of standard PD solution. The subjects in the intervention group were treated with a modified prescription, to achieve a peritoneal creatinine clearance (pCrCl) of 60 L/wk per 1.73 m(2). The primary endpoint was death. The minimal follow-up period was 2 yr. The study groups were similar with respect to demographic characteristics, causes of renal disease, prevalence of coexisting conditions, residual renal function, peritoneal clearances before intervention, hematocrit values, and multiple indicators of nutritional status. In the control group, peritoneal creatinine clearance (pCrCl) and peritoneal urea clearance (Kt/V) values remained constant for the duration of the study. In the intervention group, pCrCl and peritoneal Kt/V values predictably increased and remained separated from the values for the control group for the entire duration of the study (P < 0.01). Patient survival was similar for the control and intervention groups in an intent-to-treat analysis, with a relative risk of death (intervention/control) of 1.00 [95% confidence interval (CI), 0.80 to 1.24]. Overall, the control group exhibited a 1-yr survival of 85.5% (CI, 82.2 to 88.7%) and a 2-yr survival of 68.3% (CI, 64.2 to 72.9%). Similarly, the intervention group exhibited a 1-yr survival of 83.9% (CI, 80.6 to 87.2%) and a 2-yr survival of 69.3% (CI, 65.1 to 73.6%). An as-treated analysis revealed similar results (overall relative risk = 0.93; CI, 0.71 to 1.22; P = 0.6121). Mortality rates for the two groups remained similar even after adjustment for factors known to be associated with survival for patients undergoing PD (e.g., age, diabetes mellitus, serum albumin levels, normalized protein equivalent of total nitrogen appearance, and anuria). This study provides evidence that increases in peritoneal small-solute clearances within the range studied have a neutral effect on patient survival, even when the groups are stratified according to a variety of factors (age, diabetes mellitus, serum albumin levels, normalized protein equivalent of total nitrogen appearance, and anuria) known to affect survival. No clear survival advantage was obtained with increases in peritoneal small-solute clearances within the range achieved in this study.

Analysis of Variance↗

APD in the developing world: is there a future?

Automated peritoneal dialysis (APD) has experienced significant growth in highly developed nations in the last few years, while in developing countries with important social, educational, and financial constraints this treatment modality is, at best, trying to emerge. APD offers advantages that make it popular. Some of these advantages include increased adequacy for some patient groups, enhanced patient well-being and positive changes in lifestyle, as well as a reduction in peritonitis rates attributed to fewer connect-disconnect procedures. The development of APD in developing nations has been very poor mainly due to educational and financial constraints. APD growth as a treatment modality in the developing world requires multiple approaches, some of them general and others related to the specific needs of each nation. There is a need to develop APD research projects and pilot programs to demonstrate the benefits for specific subpopulations. In addition, the development of research and industry-market strategies directed at reducing costs related to this form of treatment are required. The relatively low use of APD in developing nations is primarily influenced by nonmedical factors. Given the financial and educational constraints, APD programs may need to be directed toward specific subpopulations such as young working adults, individuals who require assistance to perform procedures, or patients who require an increased dialysis dose in order to reach adequate clearances.

Automation↗

A time for rediscovery: chronic hemofiltration for end-stage renal disease.

Provision of maintenance renal replacement therapy (MRRT) is becoming increasingly challenging. The number of patients requiring MRRT is growing rapidly, while the number of nephrologists, nurses, and other staff available to provide therapy is not increasing at a similar rate. Patients are now older and have more comorbid conditions, which magnifies the complexity of their RRT and makes it increasingly difficult to maintain the quality of care within the limitations of constrained economic resources. The two most commonly used MRRTs are hemodialysis (HD) and peritoneal dialysis (PD). A third modality of MRRT, hemofiltration, is not currently in widespread use in North America. In hemofiltration, plasma is filtered through a highly permeable, biocompatible synthetic membrane and waste products are removed by convection and solvent drag as the filtrate moves across the membrane. Hemofiltration equipment constantly monitors the rate of plasma removal and administers a sterile, nonpyrogenic replacement solution at an appropriate rate to replace the waste-laden ultrafiltrate and avoid vdume depletion in the patient. Hemofiltration may offer some potential clinical advantages to the MRRT patient, including better hemodynamic and cardiovascular stability, enhanced removal of middle molecular weight toxins, increased comfort, and therapy preference. Some reports indicate possible reduced morbidity and mortality and reduced risk of bacterial contamination and inflammation as a result of the use of sterile, ultrapure replacement fluids. Chronic hemofiltration is a relatively simple MRRT option that may offer significant benefits for many patients who have end-stage renal disease (ESRD) and deserves closer consideration for these patients.

Hemofiltration↗