Redefining the concept of residual renal function with kidney sodium MRI: a pilot study.

RATIONALE & OBJECTIVE: The concept of residual kidney function (RKF) is exclusively based upon urine volume and small solute clearance, making RKF challenging to assess in clinical practice. The aim of this study was to test the technical feasibility of obtaining useable 23Na-MRI kidney images in hemodialysis (HD) participants. STUDY DESIGN: We conducted an exploratory prospective study to quantify the cortico-medullary sodium gradient in healthy and HD participants. Participants fasted for eight hours prior to their study visit. Urine samples were collected to measure urinary osmolarity, before MRI. Proton and sodium pictures were merged; ROIs were delineated for the medulla and cortex when feasible. In cases where cortex could not be identified, we considered the cortico to medulla gradient (CMG) to be no longer present, resulting in a medulla-to-cortex ratio of 1. SETTING & PARTICIPANTS: 17 healthy volunteers and 21 HD participants. FINDINGS: Median (IQR) fasting medulla to cortex ratio was significantly higher 1.56 [1.5-1.61] in healthy volunteers compared to HD patients 1.22 [1.13-1.3], p < 0.0001. Medulla to cortex ratio and median urinary osmolarity were correlated (r = 0.87, p < 0.0001) in the whole population. We found a significant association between HD vintage and medulla to cortex ratio whereas we did not find any association with urine volume. Sodium signal intensity distribution within healthy kidney describes two different peaks- relating to well defined cortex and medulla; whereas HD participants displays only a single peak indicative of the markedly lower sodium concentration. LIMITATIONS: This study is only an exploratory study with a modest number of patients. CONCLUSIONS: the application of kidney sodium MRI to the study of RKF in patients receiving maintenance HD is practical and provides a previously unavailable ability to interrogate the function of remnant tubular function.

A 37-year-old Menkes disease patient-Residual ATP7A activity and early copper administration as key factors in beneficial treatment.

Menkes disease (MD) is a lethal disorder characterized by severe neurological symptoms and connective tissue abnormalities; and results from malfunctioning of cuproenzymes, which cannot receive copper due to a defective intracellular copper transporting protein, ATP7A. Early parenteral copper-histidine supplementation may modify disease progression substantially but beneficial effects of long-term treatment have been recorded in only a few patients. Here we report on the eldest surviving MD patient (37 years) receiving early-onset and long-term copper treatment. He has few neurological symptoms without connective tissue disturbances; and a missense ATP7A variant, p.(Pro852Leu), which results in impaired protein trafficking while the copper transport function is spared. These findings suggest that some cuproenzymes maintain their function when sufficient copper is provided to the cells; and underline the importance of early initiated copper treatment, efficiency of which is likely to be dependent on the mutant ATP7A function.

Residual neurological function after sacral root resection during en-bloc sacrectomy: a systematic review.

PURPOSE: Sacrectomy is a highly demanding surgery representing the main treatment for primary tumors arising in the sacrum and pelvis. Unfortunately, it is correlated with loss of important function depending on the resection level and nerve roots sacrificed. The current literature regarding residual function after sacral resection comes from several small case series. The goal of this review is to appraise residual motor function and gait, sensitivity, bladder, bowel, and sexual function after sacrectomies, with consideration to the specific roots sacrificed. METHODS: An exhaustive literature search was conducted. All manuscripts published before May 2015 regarding residual function after sacrectomy were considered; if a clear correlation between root level and functioning was not present, the paper was excluded. The review identified 15 retrospective case series, totaling 244 patients; 42 patients underwent sacrectomies sparing L4/L4, L4/L5 and L5/L5; 45 sparing both L5 and one or both S1 roots; 8 sparing both S1 and one S2; 48 sparing both S2; 11 sparing both S2 and one S3, 54 sparing both S3, 9 sparing both S3 and one or both S4, and 27 underwent unilateral variable resection. RESULTS: Patients who underwent a sacrectomy maintained functionally normal ambulation in 56.2 % of cases when both S2 roots were spared, 94.1 % when both S3 were spared, and in 100 % of more distal resections. Normal bladder and bowel function were not present when both S2 were cut. When one S2 root was spared, normal bladder function was present in 25 % of cases; when both S2 were spared, 39.9 %; when one S3 was spared, 72.7 %; and when both S3 were spared, 83.3 %. Abnormal bowel function was present in 12.5 % of cases when both S1 and one S2 were spared; in 50.0 % of cases when both S2 were spared; and in 70 % of cases when one S3 was spared; if both S3 were spared, bowel function was normal in 94 % of cases. When even one S4 root was spared, normal bladder and bowel function were present in 100 % of cases. Unilateral sacral nerve root resection preserved normal bladder function in 75 % of cases and normal bowel function in 82.6 % of cases. Motor function depended on S1 root involvement. CONCLUSION: Total sacrectomy is associated with compromising important motor, bladder, bowel, sensitivity, and sexual function. Residual motor function is dependent on sparing L5 and S1 nerve roots. Bladder and bowel function is consistently compromised in higher sacrectomies; nevertheless, the probability of maintaining sufficient function increases progressively with the roots spared, especially when S3 nerve roots are spared. Unilateral resection is usually associated with more normal function. To the best of our knowledge, this is the first comprehensive literature review to analyze published reports of residual sacral nerve root function after sacrectomy.

Fractional analysis of non-linear fuzzy partial differential equations by using a direct procedure.

In this study, an accurate analytical solution is presented for fuzzy FPDEs. It is done by using a novel method called the Laplace-residual power series (LRPSM) to build a series solution to the given problems. The fundamental instruments of the employed method are the Laplace transform, fractional Laurent, and fractional power series. Using the idea of a limit at infinity, we provide a series solution to a fuzzy FPDE with quick convergence and simple coefficient finding. We analyze three cases to obtain approximate and exact solutions to show the effectiveness and reliability of the Laplace- residual power series approach. To demonstrate the accuracy of the suggested procedure, we compare the findings to the real data.

Plasma-Metanephrines in Patients with Autoimmune Addison's Disease with and without Residual Adrenocortical Function.

PURPOSE: Residual adrenocortical function, RAF, has recently been demonstrated in one-third of patients with autoimmune Addison's disease (AAD). Here, we set out to explore any influence of RAF on the levels of plasma metanephrines and any changes following stimulation with cosyntropin. METHODS: We included 50 patients with verified RAF and 20 patients without RAF who served as controls upon cosyntropin stimulation testing. The patients had abstained from glucocorticoid and fludrocortisone replacement > 18 and 24 h, respectively, prior to morning blood sampling. The samples were obtained before and 30 and 60 min after cosyntropin stimulation and analyzed for serum cortisol, plasma metanephrine (MN), and normetanephrine (NMN) by liquid-chromatography tandem-mass pectrometry (LC-MS/MS). RESULTS: Among the 70 patients with AAD, MN was detectable in 33%, 25%, and 26% at baseline, 30 min, and 60 min after cosyntropin stimulation, respectively. Patients with RAF were more likely to have detectable MN at baseline (p = 0.035) and at the time of 60 min (p = 0.048) compared to patients without RAF. There was a positive correlation between detectable MN and the level of cortisol at all time points (p = 0.02, p = 0.04, p < 0.001). No difference was noted for NMN levels, which remained within the normal reference ranges. CONCLUSION: Even very small amounts of endogenous cortisol production affect MN levels in patients with AAD.

Rate of Lung Function Decline in People with Cystic Fibrosis Having a Residual Function Gene Mutation.

INTRODUCTION: Cystic fibrosis (CF) is an autosomal recessive disease caused by mutations in the CF transmembrane conductance regulator (CFTR) gene. Approximately 5% of people with CF have residual function (RF) CFTR mutations that result in partially retained CFTR activity. Published literature on disease trajectory among those with RF mutations is limited. In this retrospective study, we characterized lung function decline across different age groups in CFTR modulator-untreated people with CF heterozygous for F508del and an RF mutation (F/RF). METHODS: Rate of decline in percent predicted forced expiratory volume in 1 s (ppFEV1) was analyzed using data from the US CF Foundation Patient Registry (2006-2014) in F/RF (all), F/RF (excluding R117H), and F508del homozygous (F/F) cohorts. Annual rates of ppFEV1 decline were estimated over 2-year periods based on calendar year. Subgroup analyses by age [6-12 (children), 13-17 (adolescents), 18-24 (young adults), and ≥ 25 years (adults)] were performed. RESULTS: The estimated annualized rate of ppFEV1 decline was - 0.70 percentage points per year (95% CI -1.09, -0.30) in the F/RF (all) cohort (N = 1242) versus -1.91 percentage points per year (95% CI -2.01, -1.80) in the F/F cohort (N = 11,916) [difference, 1.29 percentage points per year (95% CI 0.88, 1.70); P < 0.001]. In the F/RF (all) cohort, all age groups demonstrated lung function decline ranging from -0.30 to -1.38. In the F/RF (excluding R117H) cohort, the rate of decline was -1.05 percentage points per year (95% CI -1.51, -0.60) [difference versus F/F cohort, 0.95 percentage points per year (95% CI 0.48, 1.41; P < 0.001); not statistically significant in children and young adults]. CONCLUSION: Progressive lung function decline was observed in people with F/RF genotypes across all assessed age groups, reinforcing the importance of early intervention and clinical monitoring to preserve lung function in all people with CF.

In people with cystic fibrosis, lung function typically decreases over time and is linked to the severity of the disease. How fast lung function decreases (referred to as the rate of lung function decline) in cystic fibrosis depends on the specific mutations (changes) in the CFTR gene (which causes the disease). Lung function decline has been well studied in some mutation groups, but not many previous studies have looked at lung function decline in people with one copy of the F508del-CFTR mutation (which is the most common CFTR mutation and results in little to no functional CFTR protein) and another CFTR mutation called a residual function mutation (referred to as people with F/RF genotypes). We used data from the US Cystic Fibrosis Foundation Patient Registry (which collects information on the health of people in the USA who have cystic fibrosis), to look at the rate of lung function decline in people with F/RF genotypes. We found that people with cystic fibrosis who have F/RF genotypes experience lung function loss over time. We also found that this lung function loss occurred in people of all ages with F/RF genotypes. This finding supports the importance of early treatment to help prevent lung function loss in all people with cystic fibrosis, including people with F/RF genotypes.

Ivacaftor in People with Cystic Fibrosis and a 3849+10kb C→T or D1152H Residual Function Mutation.

Rationale: Ivacaftor's clinical effects in the residual function mutations 3849 + 10kb C→T and D1152H warrant further characterization.Objectives: To evaluate ivacaftor's effect in people with cystic fibrosis aged ≥6 years with 3849 + 10kb C→T or D1152H residual function mutations and to explore the correlation between ivacaftor-induced organoid-based cystic fibrosis transmembrane conductance regulator function measurements and clinical response to ivacaftor.Methods: Participants were randomized (1:1) in this placebo-controlled crossover study; each treatment sequence included two 8-week treatments with an 8-week washout period. The primary endpoint was absolute change in lung clearance index2.5 from baseline through Week 8. Additional endpoints included lung function, patient-reported outcomes, and in vitro intestinal organoid-based measurements of ivacaftor-induced cystic fibrosis transmembrane conductance regulator function.Results: Of 38 participants, 37 completed the study. The primary endpoint was met; the Bayesian posterior probability of improvement in lung clearance index2.5 with ivacaftor versus placebo was >99%. Additional endpoints improved with ivacaftor. Safety findings were consistent with ivacaftor's known safety profile. Dose-dependent swelling was observed in 23 of 25 viable organoid cultures with ivacaftor treatment. Correlations between ivacaftor-induced organoid swelling and clinical endpoints were negligible to low.Conclusions: In people with cystic fibrosis aged ≥6 years with a 3849 + 10kb C→T or D1152H mutation, ivacaftor treatment improved clinical endpoints compared with placebo; however, there was no correlation between organoid swelling and change in clinical endpoints. The organoid assay may assist in identification of ivacaftor-responsive mutations but in this study did not predict magnitude of clinical benefit for individual people with cystic fibrosis with these two mutations.Clinical trial registered with ClinicalTrials.gov (NCT03068312).

Residual Renal Function - How Fast Does the Residual Urine Output Function Decline in the First Year of Haemodialysis? - A Scoping Review.

Background: Haemodialysis is the most common treatment method in Australia for individuals requiring renal replacement therapy. Although it is known that the residual renal function in these patients has many advantages for their overall health outcomes and that the residual urine volume production is also declining over time, it is unknown how fast this functional decline occurs when patients are embarking on their first year on haemodialysis. Aim: This scoping review sought to determine if the functional decline in renal residual function in the first year of haemodialysis has been previously investigated, documented or quantified. Method: The scoping review was performed using variety of nursing and medical databases comprising MEDLINE, Embase, Web of Science and CINAHL Plus with Full Text. Results: The decline of renal residual function in patients on Peritoneal dialysis over the first year of treatment has previously been described, but not in detail for patients receiving haemodialysis. There is a paucity of knowledge how fast residual urine production can decline in patients receiving haemodialysis during their first year of treatment. A PRISMA checklist has been used to validate the results of this scoping review. Conclusions: The extended preservation of renal residual function in patients on haemodialysis is crucial for their survival and may have a positive impact on their quality of life. An observational study is needed to examine how fast the functional decrease of the residual urine production function within patients receiving haemodialysis generally occurs. This information could prove to be useful in the context of treatment goals and could inform clinical practice.

A phase 3, double-blind, parallel-group study to evaluate the efficacy and safety of tezacaftor in combination with ivacaftor in participants 6 through 11 years of age with cystic fibrosis homozygous for F508del or heterozygous for the F508del-CFTR mutation and a residual function mutation.

BACKGROUND: The CFTR modulator tezacaftor/ivacaftor was efficacious and generally safe and well tolerated in Phase 3 studies in participants ≥12 years of age with cystic fibrosis (CF) homozygous for the F508del-CFTR mutation or heterozygous with a residual function-CFTR mutation (F/F or F/RF respectively). We evaluated tezacaftor/ivacaftor's efficacy and safety over 8 weeks in participants 6 through 11 years of age with these mutations. METHODS: Participants were randomized 4:1 to tezacaftor/ivacaftor or a blinding group (placebo for F/F, ivacaftor for F/RF). The primary endpoint was within-group change from baseline in the lung clearance index 2·5 (LCI2·5) through Week 8. Secondary endpoints were change from baseline in sweat chloride (SwCl), cystic fibrosis questionnaire-revised (CFQ-R) respiratory domain score, and safety. RESULTS: Sixty-seven participants received at least one study drug dose. Of those, 54 received tezacaftor/ivacaftor (F/F, 42; F/RF, 12), 10 placebo, and 3 ivacaftor; 66 completed the study. The within-group change in LCI2·5 was significantly reduced (improved) by -0·51 (95% CI: -0·74, -0·29). SwCl concentration decreased (improved) by -12·3 mmol/L and CFQ-R respiratory domain score increased (improved, nonsignificantly) by 2·3 points. There were no serious adverse events (AEs) or AEs leading to tezacaftor/ivacaftor discontinuation or interruption. The most common AEs (≥10%) in participants receiving tezacaftor/ivacaftor were cough, headache, and productive cough. CONCLUSIONS: Tezacaftor/ivacaftor improved lung function (assessed using LCI) and CFTR function (measured by SwCl concentration) in participants 6 through 11 years of age with F/F or F/RF genotypes. Tezacaftor/ivacaftor was safe and well tolerated; no new safety concerns were identified.

Ivacaftor improves lung disease in patients with advanced CF carrying CFTR mutations that confer residual function.

BACKGROUND: Ivacaftor is an innovative treatment for CF. Ivacaftor monotherapy in a phase III trial for patients with F508del and a residual function (RF) mutation showed improvement in lung function. We evaluated the effectiveness and safety of ivacaftor in patients with severe CF carrying RF mutations. METHODS: Data were collected from Italian CF centers with patients enrolled in an ivacaftor compassionate use program. Data were collected 1 year before and 1 year after commencement of ivacaftor. RESULTS: Twenty-six patients received ivacaftor. The mean [standard deviation (SD)] percent predicted FEV1 significantly increased from 33.9% (8.3) before treatment to 44.0% (10.7) after 12 months of treatment (p < 0.00001). The mean distance in the 6-min walking-test significantly improved from 458.2 (110.5) m at baseline to 524.8 (91.9) m after 12 months (p < 0.00001). The overall number of days of antibiotic therapy decreased from 1693 during the year before ivacaftor to 714 in the year following ivacaftor, and the number of days of intravenous antibiotic treatment dropped from 714 to 88; both results were statistically significant (p < 0.00001). Patients needing intravenous therapy decreased from 23 to 5 of 26. The mean (SD) sweat chloride level decreased from a baseline of 79 (22.3) mmol/L to 65 (30.6) mmol/L, but this variation was not significant (p = 0.26). No safety concerns were registered. CONCLUSIONS: In patients with CFTR mutations that confer RF with severe lung disease, treatment with Ivacaftor is safe and results in a clinically significant improvement that was evident at 1 month and maintained at 12 months.

Residual Corticosteroid Production in Autoimmune Addison Disease.

CONTEXT: Contrary to current dogma, growing evidence suggests that some patients with autoimmune Addison disease (AAD) produce corticosteroids even years after diagnosis. OBJECTIVE: To determine frequencies and clinical features of residual corticosteroid production in patients with AAD. DESIGN: Two-staged, cross-sectional clinical study in 17 centers (Norway, Sweden, and Germany). Residual glucocorticoid (GC) production was defined as quantifiable serum cortisol and 11-deoxycortisol and residual mineralocorticoid (MC) production as quantifiable serum aldosterone and corticosterone after > 18 hours of medication fasting. Corticosteroids were analyzed by liquid chromatography-tandem mass spectrometry. Clinical variables included frequency of adrenal crises and quality of life. Peak cortisol response was evaluated by a standard 250 µg cosyntropin test. RESULTS: Fifty-eight (30.2%) of 192 patients had residual GC production, more common in men (n = 33; P < 0.002) and in shorter disease duration (median 6 [0-44] vs 13 [0-53] years; P < 0.001). Residual MC production was found in 26 (13.5%) patients and associated with shorter disease duration (median 5.5 [0.5-26.0] vs 13 [0-53] years; P < 0.004), lower fludrocortisone replacement dosage (median 0.075 [0.050-0.120] vs 0.100 [0.028-0.300] mg; P < 0.005), and higher plasma renin concentration (median 179 [22-915] vs 47.5 [0.6-658.0] mU/L; P < 0.001). There was no significant association between residual production and frequency of adrenal crises or quality of life. None had a normal cosyntropin response, but peak cortisol strongly correlated with unstimulated cortisol (r = 0.989; P < 0.001) and plasma adrenocorticotropic hormone (ACTH; r = -0.487; P < 0.001). CONCLUSION: In established AAD, one-third of the patients still produce GCs even decades after diagnosis. Residual production is more common in men and in patients with shorter disease duration but is not associated with adrenal crises or quality of life.

Long-Term Ivacaftor in People Aged 6 Years and Older with Cystic Fibrosis with Ivacaftor-Responsive Mutations.

INTRODUCTION: Mutations in the cystic fibrosis transmembrane conductance regulator gene (CFTR) affect the quantity and/or function of CFTR protein reaching the cell surface. Ivacaftor, a CFTR potentiator that enhances chloride transport, increases the channel-open probability of normal and dysfunctional CFTR. Initially approved for people with CF (pwCF) with G551D-CFTR gating mutations, ivacaftor demonstrated clinical benefit in pwCF with other gating mutations and certain residual function mutations, including R117H-CFTR, in clinical studies. We evaluated the long-term safety and efficacy of ivacaftor in pwCF aged 6 years and older with non-G551D-CFTR ivacaftor-responsive mutations. METHODS: Efficacy and safety data from a phase 3, multicenter, open-label, extension study for participants from Study 110 (R117H-CFTR mutations), Study 111 (non-G551D-CFTR gating mutations), and Study 113 (n-of-1 pilot study in participants with residual CFTR function) were analyzed. Following washout from the randomized parent study, participants received oral ivacaftor 150 mg once every 12 h for 104 weeks. RESULTS: Forty-one of 121 participants completed treatment through 104 weeks; 59 participants who did not complete the extension study continued treatment with commercial ivacaftor. The most common adverse events were pulmonary exacerbation (46.3%) and cough (33.9%). Most treatment-emergent adverse events were mild/moderate in severity and consistent with manifestations of CF or the ivacaftor safety profile. Rapid, durable improvement occurred across all efficacy endpoints. CONCLUSIONS: Ivacaftor was generally safe and well tolerated with no new safety concerns for up to 104 weeks in pwCF with ivacaftor-responsive mutations. The pattern of improvement across efficacy endpoints was durable and generally consistent with parent-study outcomes. TRIAL REGISTRATION: NCT01707290.

Patients with cystic fibrosis having a residual function mutation: Data from the Italian registry.

BACKGROUND: CFTR mutations permitting residual function (RF) of the CFTR protein are disease-causing. These mutations are associated with a pneumopathy that is delayed in onset and is slower in progression than are more common forms of cystic fibrosis (CF), although the disease may become severe in some patients. RF mutations are among the most frequent in Italy, thus encouraging investigation of their prevalence and associated phenotypes. METHODS: Data from the Italian Registry were used to compare patients with at least one RF mutation with those homozygous for F508del. RESULTS: A total of 806 patients bearing at least one RF mutation were identified among 5204 registered patients (15.5%). The RF patients were older than the F508del homozygotes (median age 26.0 years vs 19.8 years, respectively), with a higher median age at diagnosis (6.3 years vs 0.2 years, respectively) and a lower median sweat chloride value (76.0 mmol/L vs 100.0 mmol/L, respectively). In the RF group, lung infections and comorbidities were less prevalent than those in the F508del homozygotes, while better FEV1 and nutritional status were observed at all ages. Within the RF group, RF/F508del subjects showed more severe pneumopathy than did patients with RF/other mutations. In particular, the 3849 + 10kbC → T/F508del subjects had worse FEV1 and a higher prevalence of lung infections than did patients with other genotypes. CONCLUSIONS: Patients with RF mutations are numerous in Italy and have a milder disease phenotype than do F508del homozygotes. Inside the RF group, F508del heterozygotes and, in particular, 3849 + 10kbC → T/F508del patients showed more severe pneumopathy.

New global error bound for extended linear complementarity problems.

For the extended linear complementarity problem (ELCP), by virtue of a new residual function, we establish a new type of global error bound under weaker conditions. Based on this, we respectively obtain new global error bounds for the vertical linear complementarity problem and the mixed linear complementarity problem. The obtained results presented in this paper supplement some recent corresponding results in the sense that they can provide some error bounds for a more general ELCP. Their feasibility is verified by some numerical experiments.

Ivacaftor restores CFTR-dependent sweat gland fluid secretion in cystic fibrosis subjects with S945L alleles.

BACKGROUND: To determine in vivo effects of CFTR modulators on mutation S945L. METHODS: We measured effects of CFTR modulators on CFTR-dependent sweating ('C-sweat') in two pancreatic sufficient cystic fibrosis (CF) subjects. S1 (S945L/G542X) took ivacaftor and S2 (S945L/F508del) took ivacaftor+tezacaftor. Sweating was stimulated pharmacologically to produce sequentially both CFTR-independent (methacholine stimulated) M-sweat and C-sweat; and the ratio of these was compared. Sweat secretion was measured with two methods: real time secretory rate quantitative recording and by optically measuring the growth of sweat bubbles under oil from multiple identified glands. RESULTS: Using the quantitative recorder, we saw zero C-sweat secretion off-drug, but when on-drug the C-sweat responses for both subjects were comparable to those seen in carriers. The on-drug response was further quantified using the sweat bubble method. Each subject again showed robust C-sweat responses, with C-sweat/M-sweat ratios~half of the ratio determined for a cohort of 40 controls tested under identical conditions. CONCLUSION: These in vivo results, consistent with prior in vitro findings, indicate that the drug treatments restore near-normal function to S945L-CFTR, and support the use of ivacaftor as a treatment for CF patients who carry this allele.

Is sweat chloride predictive of severity of cystic fibrosis lung disease assessed by chest computed tomography?

BACKGROUND: Cystic Fibrosis (CF) lung disease is characterized by a marked heterogeneity. Sweat chloride-level is a functional marker of the CF Transmembrane Regulator (CFTR) protein and could be an important predictor of later disease severity. METHODS: In this retrospective analysis children from the Rotterdam CF clinic with available sweat chloride level at diagnosis and at least one routine spirometry-controlled volumetric chest CT scan in follow-up were included. CT scans were scored using the CF-CT scoring system (% of maximum). Associations between sweat chloride-levels and CF-CT scores were calculated using linear regression models, adjusting for age at sweat test and age at follow-up. Because structural lung damage develops over the course of many years, effect modification by the age at follow-up CT-scan was tested for by age-stratification. RESULTS: In 59 children (30 male) sweat chloride was measured at diagnosis (median age 0.5 years, range 0-13) and later chest CT performed (median age 14 years, range 6-18). Sweat chloride was associated with significantly higher CT-CT total score, bronchiectasis score, and mucus plugging score. Stratification for age at follow-up in tertiles showed this association remained only in the oldest age group (range 15-18 years). In that subgroup associations were found with all but one of the CF-CT subscores, as well as with all tested lung functions parameters. CONCLUSION: Sweat chloride-level is a significant predictor of CF lung disease severity as determined by chest CT and lung function. This association could only be demonstrated in children with follow-up to age 15 years and above.

The use of ivacaftor in CFTR mutations resulting in residual functioning protein.

INTRODUCTION: Ivacaftor, a cystic fibrosis transmembrane regulator (CFTR) potentiator is currently approved for use in individuals with class III gating mutations and the R117H mutation, a non-gating mutation with residual functioning CFTR. Nevertheless, ivacaftor may also be effective in individuals who have CF mutations giving rise to a residual functioning protein. However, aside from case reports involving a single patient, little data exist on the use of ivacaftor in such individuals. METHODS: A real life pragmatic report wherein seven adults with mutations resulting in a CFTR with residual function were prescribed ivacaftor. Four individuals with similar mutations acted as comparison. We assessed lung function, body mass index, sweat chloride; the number of acute respiratory exacerbations and health related quality of life. RESULTS: Patients with residual functioning CFTR showed significant improvement or stabilization in all parameters up to 3 years following the start of ivacaftor. Those with similar mutations and who did not receive ivacaftor worsened. CONCLUSION: We report the use of ivacaftor in seven adults with various Class IV and V non-gating CFTR mutation with residual functioning protein and we demonstrate improvement in several clinical parameters.

La función renal residual en diálisis peritoneal / Residual renal uunction in peritoneal dialysis

Una mayor función renal residual (FRR) al comenzar el programa de diálisis y su persistencia durante dicho tratamiento, mejora el pronóstico y disminuye la mortalidad de los pacientes OBJETIVOS: PRINCIPAL: Determinarla (FRR) de pacientes en diálisis peritoneal intrahospitalaria (DPI) del Hospital Obrero No 1, Caja Nacional de Salud (CNS) La Paz, Bolivia. SECUNDARIOS: Determinar la relación de la FRR con el estado nutricional, morbilidad, anemia, pronóstico y sobrevida. MATERIAL Y MÉTODOS Tipo de estudio: Analítico, transversal. Universo: El total de pacientes en DPI (28) del Hospital Obrero No 1 CNS. Tiempo: Del 1 de enero al 31 de diciembre de 2010. Metodología: Estimar la FRR, mediante gammagrafía renal. Cálculo del Kt/V y de la tasa de catabolismo proteico (TCP). Determinar la morbilidad asociada. El análisis estadístico: determinación de P de Pearson, regresión multivariable, valor P significativo < 0.05 RESULTADOS Los pacientes en DPI del Hospital Obrero No 1, fueron 28, el 56% del sexo femenino y 44% del sexo masculino, la edad promedio 56+/- 7.8 años (rango 16 a 86 años), el tiempo promedio de permanencia en diálisis fue de 3+/-1.5 años (rango 1 mes a 6.5 años). La FRR estuvo aun presente en 66% con un promedio de 5.6+/-1.28 ml/min, el volumen urinario residual fue de 1250+/-125 ml/24 horas, KtV 0.95+/-0.05. El 68% tenían TCP de 0.71+/-0.0112. La morbilidad detectada al momento del estudio: hipertensión, cardiopatía isquémica crónica y anemia. Esto fue más evidente en el grupo que no tenía función renal residual (34%, P<0,05). El análisis estadístico evidenció mejor estado nutricional, menor morbilidad y menor grado de anemia en pacientes con función renal residual que los que no la tenían (P< 0.05). CONCLUSIONES Se confirmó la importancia de mantener la función renal residual que se relaciona con un mejor estado nutricional, menor morbilidad, menor grado de anemia, pronóstico y sobrevida.

Greater residual renal function at the beginning of the dialysis program and its persistence in such treatment improves outcome and reduces mortality of patients. OBJECTIVES: Mesure residual renal function in peritoneal dialysis patients at Obrero No 1 Hospital, CNS, La Paz, Bolivia. Determine the relationship of residual renal function with nutritional status, morbidity, anemia, prognosis and survival. MATERIAL AND METHODS Type of study: Analytical, cross. Studied population: Total patients in peritoneal dialysis (28) of the Obrero Hospital N° 1, CNS. Period of time for the investigation: January 1 to December 31, 2010. Methodology: Measure the residual renal function by renal scintigraphy, Kt/V and protein catabolic rate on line. Determine the associated morbidity. Statistical analysis: Pearson's P, multivariate regression, significant P value <0.05. RESULTS The patients in peritoneal dialysis of Obrero Working Hospital No 1, were 28; female 56 %, male 44 %, the average age 56 +/-7.8 years (range 16 to 86 years), average time of permanency in dialysis 3 +/-1.5 years (range 1 month to 6.5 years). The Residual Renal Function even present in 66 %, average 5.6 +/-1.28 ml/min, the urinary residual volume was of1250 +/-125 ml/24 hours, KtV0.95 +/-0.05. Sixty eight percent had TCP of 0.71 +/-0.0112. The morbidity detected at moment of the study: hypertension ischemic chronicle heart disease and anemia. This was more evident in the group that did not have renal residual function (34 %, P <0,05). The statistical analysis demonstrate better nutritional condition, minor morbidity and minor intensity of anemia in patients with renal residual function that those who did not have their (P <0.05). CONCLUSIONS Was confirmed the importance of supporting the renal residual function that relates to better nutritional condition, minor morbidity, minor intensity of anemia, prognosis and survival.