New stationary phases for efficient separations and selectivity studies in anion chromatography

Spacer arm anion-exchange resins for single-column ion chromatography (SCIC) were prepared by a two-step procedure consisting of a bromoalkylation of Rohm & Haas XAD-1 resin under mild conditions, followed by amination with trimethylamine. The five resins prepared are all of a similar, low capacity and contain a one-, two-, three-, four- or six-carbon spacer arm linkage between the resin surface and the quaternary ammonium exchange group. The selectivity of these resins for mono- and divalent anions is evaluated and explained using classical ion-exchange theory. Separations are presented to demonstrate resin selectivity and to show the usefulness of these resins for practical ion chromatography;Trimethylammonium, tributylammonium and tributylphosphonium anion-exchange resins were synthesized and used for SCIC. The three resins were prepared using a 7 to 12 [mu]m polystyrene-divinylbenzene resin and are all of a similar, low capacity. The selectivity of these resins for mono- and divalent anions is examined and related to classical theory. It is shown that the unique selectivity obtained with the quaternary phosphonium resin is of practical value in the separation of anions;A new stationary phase for anion chromatography was prepared by a simple method of coating quaternized latex particles onto the surface of unsulfonated polymeric resins. A nonporous polystyrene resin of very uniform particle size is described that serves as an excellent substrate for the coated resins. These latex-coated resins are used to obtain highly efficient anion separations

Distinct Mitochondrial Pathologies Caused by Mutations of the Proximal Tubular Enzymes EHHADH and GATM

The mitochondria of the proximal tubule are essential for providing energy in this nephron segment, whose ATP generation is almost exclusively oxygen dependent. In addition, mitochondria are involved in a variety of metabolic processes and complex signaling networks. Proximal tubular mitochondrial dysfunction can therefore affect renal function in very different ways. Two autosomal dominantly inherited forms of renal Fanconi syndrome illustrate how multifaceted mitochondrial pathology can be: Mutation of EHHADH, an enzyme in fatty acid metabolism, results in decreased ATP synthesis and a consecutive transport defect. In contrast, mutations of GATM, an enzyme in the creatine biosynthetic pathway, leave ATP synthesis unaffected but do lead to mitochondrial protein aggregates, inflammasome activation, and renal fibrosis with progressive renal failure. In this review article, the distinct pathophysiological mechanisms of these two diseases are presented, which are examples of the spectrum of proximal tubular mitochondrial diseases

A Novel Y152C KCNJ5 Mutation Responsible for Familial Hyperaldosteronism Type III

CONTEXT: Primary aldosteronism is a heterogeneous group of disorders comprising both sporadic and familial forms. Mutations in the KCNJ5 gene, which encodes the inward rectifier K(+) channel 4 (G protein-activated inward rectifier K(+) channel 4, Kir3.4), cause familial hyperaldosteronism type III (FH-III) and are involved in the pathogenesis of sporadic aldosterone-producing adenomas. OBJECTIVE: The objective of the study was to characterize the effects of a newly described KCNJ5 mutation in vitro. PATIENTS AND METHODS: The index case is a 62-year-old woman affected by primary aldosteronism, who underwent left adrenalectomy after workup for adrenal adenoma. Exon 1 of KCNJ5 was PCR amplified from adrenal tissue and peripheral blood and sequenced. Electrophysiological and gene expression studies were performed to establish the functional effects of the new mutation on the membrane potential and adrenal cell CYP11B2 expression. RESULTS: KCNJ5 sequencing in the index case revealed a new p.Y152C germline mutation; interestingly, the phenotype of the patient was milder than most of the previously described FH-III families. The tyrosine-to-cysteine substitution resulted in pathological Na(+) permeability, cell membrane depolarization, and disturbed intracellular Ca(2+) homeostasis, effects similar, albeit smaller, to the ones demonstrated for other KCNJ5 mutations. Gene expression studies revealed an increased expression of CYP11B2 and its transcriptional regulator NR4A2 in HAC15 adrenal cells overexpressing KCNJ5(Y152C) compared to the wild-type channel. The effect was clearly Ca(2+)-dependent, because it was abolished by the calcium channel blocker nifedipine. CONCLUSIONS: Herein we describe a new germline mutation in KCNJ5 responsible for FH-III

CARACTERIZAÇÃO SOROLÓGICA DOS ANTÍGENOS DE SUPERFÍCIE EM CEPAS DE ESCHERICHIA COLI ISOLADAS DE SUÍNOS COM DIARRÉIA NO ESTADO DO PARANÁ

The aim of the present work wasthe serological characterization of 42 strains ofEscherichia coli isolated at the Center of VeterinaryDiagnostic Marcos Enrietti, in Curitiba, PR from outbreaks of swine diarrhea in the State of Paraná. Thesurface O-K and adherence antigens were identifiedat the Center of Veterinary Researches DesidérioFinamor (RS) and at UNICAMP (SP), respectively.The main serogroups involved were O138:K81 andO141:K85 which occurred in the same proportion in9 (21.4%) strains; 4 (9.5%) strains were O139:K82and 3 (7.1%) were O149:K91. The serogroupsO35:K”V79”, O108:K”V189”, O115:K”V165” andO119:K”V113” were found in only one sample each(2.4%) of the strains. In relation to fimbrial antigens,K88 was detected in 22 (52.4%) strains and theF165 in 5 (11.9%) strains. This is the first report ofthe occurrence of the fimbrial antigen named F165in Brazil. It was concluded that the inclusion ofthese more prevalent serogroups O-K as well as theclassical fimbriae and the F165 antigen could givemore protection against the colibacillosis of pigletsin Parana State.O presente trabalho teve como objetivoa caracterização sorológica de 42 cepas deEscherichia coli isoladas no Centro de DiagnósticoMarcos Enrietti em Curitiba, PR de surtos de diarréiasuína no Estado do Paraná. Os antígenos desuperfície O-K e de aderência foram identificadosno Centro de Pesquisas Veterinárias Desidério Finamor(RS), e na UNICAMP (SP), respectivamente.Os principais sorogrupos mais prevalentes foramO138:K81 e O141:K85, ocorrendo na mesmaproporção, em 9 (21,4%) cepas; O139:K82 em 4(9,5%) e O149:K91 em 3 (7,1%) totalizando 25(59,4%) cepas. Os sorogrupos menos prevalentestotalizaram 4 (9,5%) cepas e foram identificadoscomo O35:K”V79”, O108:K”V189”, O115:K”V165” eO119:K”V113”. Quanto aos antígenos de aderência,a fímbria K88 foi detectada em 22 (52,4%) cepas. Oantígeno F165 ocorreu em 5 (11,9%) cepas sendoeste o primeiro relato da ocorrência deste antígenoem cepas ETEC infectando suínos no Brasil. Baseadono levantamento sorológico concluiu-se quea inclusão nas vacinas dos sorogrupos O-K maisprevalentes e dos antígenos de aderência clássicosbem como do F165 poderá conferir proteção maisefetiva na prevenção da colibacilose dos leitões noEstado do Paraná

Methods for the study of ionic currents and Ca(2+)-signals in isolated colonic crypts

Isolated epithelial cells from intestinal mucosae are a suitable object for the study of the regulation of ion transport in the gut. This regulation possesses a great importance for human and veterinary medicine, as diarrheal diseases, which often are caused by an inadequate activation of intestinal anion secretion, are one of the major lethal diseases of children or young animals. The aim of this paper is to describe a method for the isolation of intact colonic crypts, e.g. for the subsequent investigation of the regulation of anion secretion by the intracellular second messenger, Ca(2+) using electrophysiological and imaging techniques

Renal Fanconi syndrome: taking a proximal look at the nephron

Renal Fanconi syndrome (RFS) refers to the generalized dysfunction of the proximal tubule (PT) (Kleta R. Fanconi or not Fanconi? Lowe syndrome revisited. Clin J Am Soc Nephrol 2008; 3: 1244-1245). In its isolated form, RFS only affects the PT, but not the other nephron segments. The study of isolated RFS can thus provide specific insights into the function of the PT. In a recent paper, Klootwijk et al. investigated one such form of isolated RFS and revealed the underlying molecular basis (Klootwijk ED, Reichold M, Helip-Wooley A et al. Mistargeting of peroxisomal EHHADH and inherited renal Fanconi's syndrome. N Engl J Med 2014; 370: 129-138). The affected family had been described previously, demonstrating the typical features of RFS, such as low-molecular weight proteinuria, aminoaciduria, glycosuria and phosphaturia with consequent rickets; yet, importantly, patients had no evidence of impaired glomerular filtration (Tolaymat A, Sakarcan A, Neiberger R. Idiopathic Fanconi syndrome in a family. Part I. Clinical aspects. J Am Soc Nephrol 1992; 2: 1310-1317). Inheritance was consistent with an autosomal dominant mode. Klootwijk et al. discovered a surprising explanation: a heterozygous missense mutation causing partial mistargeting of the peroxisomal enzyme EHHADH to the mitochondria. Notably, disease causing was not the absence of the enzyme in the peroxisome, but its interference with mitochondrial function. The discovery of this novel disease mechanism not only confirmed the importance of mitochondrial function for PT transport, but also demonstrated the critical dependence of PT on fatty acid metabolism for energy generation

Fixed-bearing Medial Unicompartmental Knee Arthroplasty Restores Neither the Medial Pivoting Behavior Nor the Ligament Forces of the Intact Knee in Passive Flexion

Medial unicompartmental knee arthroplasty (UKA) is an accepted treatment for isolated medial osteoarthritis. However, using an improper thickness for the tibial component may contribute to early failure of the prosthesis or disease progression in the unreplaced lateral compartment. Little is known of the effect of insert thickness on both knee kinematics and ligament forces. Therefore, a computational model of the tibiofemoral joint was used to determine how non-conforming, fixed bearing medial UKA affects tibiofemoral kinematics and tension in the medial collateral ligament (MCL) and the anterior cruciate ligament (ACL) during passive knee flexion. Fixed bearing medial UKA could not maintain the medial pivoting that occurred in the intact knee from 0° to 30° of passive flexion. Abnormal anterior-posterior (AP) translations of the femoral condyles relative to the tibia delayed coupled internal tibial rotation, which occurred in the intact knee from 0° to 30° flexion, but occurred from 30° to 90° flexion following UKA. Increasing or decreasing tibial insert thickness following medial UKA also failed to restore the medial pivoting behavior of the intact knee despite modulating MCL and ACL forces. Reduced AP constraint in non-conforming medial UKA relative to the intact knee leads to abnormal condylar translations regardless of insert thickness even with intact cruciate and collateral ligaments. This finding suggests that the conformity of the medial compartment as driven by the medial meniscus and articular morphology plays an important role in controlling AP condylar translations in the intact tibiofemoral joint during passive flexion