A series of patients with minimal change nephropathy treated with rituximab during adolescence and adulthood

Background

The treatment of immune suppression dependent minimal change nephropathy (MCN) can be challenging and frequently leads to serious complications. In paediatric patients, successful treatment with rituximab is described in steroid-dependent MCN. There is limited information about the potential efficacy of rituximab for the treatment of MCN in adults and adolescence. We describe our experience with rituximab in adolescent and adult patients with immune suppression dependent MCN.

Results

Ten adolescents and adults with immune suppression dependent MCN and therapy related complications were treated with rituximab. At a mean age of 26 years, about 10.5 years after first presentation, they received two doses of rituximab (375 mg/m²). Maintenance immunosuppressive medication was stopped. After a mean follow-up of 43 months, three patients had four relapses. Three relapses were successfully retreated with rituximab again, after induction therapy with 60 mg prednisone per day. Rituximab was well tolerated and no infectious complications were recorded.

Conclusion

Treatment with rituximab induces a long-term remission of immune suppression dependent MCN in adolescents and adults. A timely treatment with rituximab could be considered to limit side effects of immunosuppressive medication.

     

Urinary and plasma proteomics to discover biomarkers for diagnosing between diabetic nephropathy and minimal change nephrotic syndrome or membranous nephropathy

The choice of treatment for primary nephrotic syndrome depends on the pathologic type of the disorder. Renal biopsy is necessary for a definitive diagnosis, but it is burdensome for the patients, and can be avoided if tests could be performed using urine or plasma. In this study, we analyzed 100 urinary proteins, 141 plasma proteins, and 57 urine/plasma ratios in cases of diabetic nephropathy (DN; n = 11), minimal change nephrotic syndrome (MCNS; n = 14), and membranous nephropathy (MN; n = 23). We found that the combination of urinary retinol-binding protein 4 and SH3 domain-binding glutamic acid-rich-like protein 3 could distinguish between MCNS and DN, with an area under the curve (AUC) of 0.9740. On the other hand, a selectivity index (SI) based on serotransferrin and immunoglobulin G, which is often used in clinical practice, distinguished them with an AUC of 0.9091. Similarly, the combination of urinary afamin and complement C3 urine/plasma ratio could distinguish between MN and DN with an AUC of 0.9842, while SI distinguished them with an AUC of 0.8538. Evidently, the candidates identified in this study were superior to the SI method. Thus, the aim was to test these biomarkers for accurate diagnosis and to greatly reduce the burden on patients.     

MTHFR gene variant is not associated with diabetic nephropathy in Japanese.

Genetic predisposition has been implicated in diabetic nephropathy. The C677T variant of the MTHFR gene has been suggested to play a role in the development of not only vascular diseases but also diabetic microangiopathies. By using polymerase chain reaction-restriction length polymorphism (PCR-RFLP) method using Hinf I, we investigated whether this variant is associated with diabetic nephropathy in Japanese. By analysing 274 unrelated Japanese patients with type II DM with or without nephropathy, there was no significant difference in the genotype distribution of this variant. The distribution of the three genotypes were not different among patients with micro- or macroalbuminuria and those without nephropathy. Although previous reports suggest a role of this variant with diabetic microangiopathies, our observations suggest that this variant is does not play an important role in the pathogenesis of diabetic nephropathy in Japanese.     

糖尿病肾病患者与相关细胞因子水平的变化

目的:研究糖尿病肾病(DN)患者的血清肿瘤坏死因子(TNF-α)、干扰素-γ(IFN-γ)、白介素-6(IL-6)、血管内皮生长因子(VEGF)、和肝细胞生长因子(HGF)水平的变化在肾病发生、发展过程中的作用。方法:应用ELISA法分析20例糖尿病肾病患者和20例正常人进行了血清TNF-α、IFN-γ、IL-6、VEGF和HGF水平。结果:糖尿病肾病患者血清中TNF-α、IL-6、VEGF和HGF水平非常显著地高于正常人组(P<0.01),而IFN-γ水平则显著地低于正常人组(P<0.01)。结论:TNF-α、IFN-γ、IL-6、VEGF和HGF水平的变化在糖尿病肾病的发生和发展中相互作用,观察其浓度的变化对探讨其发病机理、预防和指导导用药均有十分重要的临床价值。     

Isolated ACTH deficiency associated with transient thyrotoxicosis and hyperprolactinemia

A 43-year-old woman with isolated ACTH deficiency in association with transient thyrotoxicosis is reported. The initial evaluation revealed that plasma ACTH and cortisol did not respond to corticotropin-releasing hormone (CRH) in the presence of hyperthyroxinemia and hyperprolactinemia. During the replacement therapy with dexamethasone, she developed transient hypothyroxinemia with persistent hyperprolactinemia. Although thyroid open biopsy did not show any evidence of autoimmune thyroiditis or subacute thyroiditis, the data appear to provide other evidence of a possible relationship between acute adrenal insufficiency and transient thyroid dysfunction.     

Germline p53 single-base changes associated with Balkan endemic nephropathy

The Balkan endemic nephropathy (BEN) is a significant clinical and scientific problem in need of novel effective therapies. Though many genetic and environmental factors have been investigated the basis, cause, and predisposition to BEN are still unclear. In this study, based on the hypothesis that the genetic pathways leading to BEN might be associated with p53 dysfunction, we screened for p53 gene mutations 90 Bulgarian BEN patients using optimized PCR-SSCP-sequencing analysis. Germline p53 single-base changes were found in blood samples in 10% of BEN cases. Three of them caused amino acid substitutions (p.Arg283Cys, p.Gln317His, and p.Lys321Glu); the other six were either synonymous amino acid substitutions (p.Arg213Arg) or intron polymorphisms (T14766C). To the best of our knowledge, these are the first data investigating tumor suppressor gene mutations in patients with BEN. The obtained results are in support of our hypothesis that p53 gene alterations are possibly involved in BEN genetic pathways.     

Targeted genome-wide investigation identifies novel SNPs associated with diabetic nephropathy

Loci contributing to complex disease have been identified by focusing on genome-wide scans utilising non-synonymous single nucleotide polymorphisms (nsSNPs). We employed Illumina's HNS12 BeadChip (13,917 high-value SNPs) which was specifically designed to capture nsSNPs and ideally complements more dense genome-wide association studies that fail to consider many of these putatively functional variants. The HNS12 panel also includes 870 tag SNPs covering the major histocompatibility region. All individuals genotyped in this study were Caucasians with (cases) and without (controls) diabetic nephropathy. About 449 individuals with type 2 diabetes (203 cases, 246 controls) were genotyped in the initial study. 1,467 individuals with type 1 diabetes (718 cases, 749 controls) were genotyped in the follow up study. 11,152 SNPs were successfully analysed and ranked for association with diabetic nephropathy based on significance (P) values. The top ranked 32 SNPs were subsequently genotyped using MassARRAY iPLEX(?) and TaqMan technologies to investigate association of these polymorphisms with nephropathy in individuals with type 1 diabetes. The top ranked nsSNP, rs1543547 (P?=?10(-5)), is located in RAET1L, a major histocompatibility class I-related gene at 6q25.1. Of particular interest, multiple nsSNPs within the top ranked (0.2%) SNPs are within several plausible candidate genes for nephropathy on 3q21.3 and 6p21.3.     

A minimal bacterial RNase J-based degradosome is associated with translating ribosomes

Protein complexes directing messenger RNA (mRNA) degradation are present in all kingdoms of life. In Escherichia coli, mRNA degradation is performed by an RNA degradosome organized by the major ribonuclease RNase E. In bacteria lacking RNase E, the existence of a functional RNA degradosome is still an open question. Here, we report that in the bacterial pathogen Helicobacter pylori, RNA degradation is directed by a minimal RNA degradosome consisting of Hp-RNase J and the only DExD-box RNA helicase of H. pylori, RhpA. We show that the protein complex promotes faster degradation of double-stranded RNA in vitro in comparison with Hp-RNase J alone. The ATPase activity of RhpA is stimulated in the presence of Hp-RNase J, demonstrating that the catalytic capacity of both partners is enhanced upon interaction. Remarkably, both proteins are associated with translating ribosomes and not with individual 30S and 50S subunits. Moreover, Hp-RNase J is not recruited to ribosomes to perform rRNA maturation. Together, our findings imply that in H. pylori, the mRNA-degrading machinery is associated with the translation apparatus, a situation till now thought to be restricted to eukaryotes and archaea.     

Congenital infection of mice with Toxoplasma gondii induces minimal change in behavior and no change in neurotransmitter concentrations

We examined the effect of maternal Toxoplasma gondii infection on behavior and the neurotransmitter concentrations of congenitally infected CD-1 mice at 4 and 8 wk of age when latent tissue cysts would be present in their brains. Because of sex-associated behavioral changes that develop during aging, infected female mice were compared with control females and infected male mice were compared with control males. Only the short memory behavior (distance between goal box and first hole investigated) of male mice congenitally infected with T. gondii was significantly different (P < 0.05) from that of uninfected control males at both 4 and 8 wk by using the Barnes maze test. The other parameters examined in the latter test, i.e., functional observational battery tests, virtual cliff, visual placement, and activity tests, were not significantly different (P > 0.05) at 4 and 8 wk. Concentrations of neurotransmitters and their metabolites (dopamine; 3,4-dihydroxyphenylacetic acid; homovanillic acid; norepinephrine; epinephrine; 3-methoxy-4-hydroxyphenylglycol; serotonin; and 5-hydroxyindoleacetic acid) in the frontal cortex and striatum were not different (P > 0.05) between infected and control mice at 8 wk of age. The exact mechanism for the observed effect on short-term memory in male mice is not known, and further investigation may help elucidate the molecular mechanisms associated with the proposed link between behavioral changes and T. gondii infection in animals. We were not able, however, to confirm the widely held belief that changes in neurotransmitters result from chronic T. gondii infection of the brain.     

Adenylate cyclase toxin from Bordetella pertussis. Conformational change associated with toxin activity

Adenylate cyclase (AC) toxin from Bordetella pertussis interacts with and enters eukaryotic cells to catalyze the production of supraphysiologic levels of cyclic AMP. Although the calmodulin-activated enzymatic activity (ability to convert ATP to cyclic AMP in a cell-free assay) of this molecule is calcium independent, its toxin activity (ability to increase cyclic AMP levels in intact target cells) requires extracellular calcium. Toxin activity as a function of calcium concentration is biphasic, with no intoxication occurring in the absence of calcium, low level intoxication (200-300 pmol of cyclic AMP/mg of Jurkat cell protein) occurring with free calcium concentrations between 100 nM and 100 microM and a 10-fold increase in AC toxin activity at free calcium concentrations above 300 microM. The molecule exhibits a conformational change when free calcium concentrations exceed 100 microM as demonstrated by shift in intrinsic tryptophan fluorescence, an alteration in binding of one anti-AC monoclonal antibody, protection of a fragment from trypsin-mediated proteolysis, and a structural modification as illustrated by electron microscopy. Thus, it appears that an increase in the ambient calcium concentration to a critical point and the ensuing interaction of the toxin with calcium induces a conformational change which is necessary for its insertion into the target cell and for delivery of its catalytic domain to the cell interior.     

Regulation of aspartate aminotransferase activity associated with change of pyridoxal phosphate level.

The activities of aspartate aminotransferase (EC 2.6.1.1) in the cytosol fractions of the liver and kidney of rats fed pyridoxine-deficient or control diet for 3 weeks were determined. In the absence of pyridoxal phosphate, the activities in the liver and kidney preparations of deficient rats were both abnormally low. The activity in the kidney fraction of deficient rats was restored to almost the control level by addition of pyridoxal phosphate, whereas that of the liver was only partially restored. The antigen activity, however, measured using anti-aspartate aminotransferase, was similar in liver fractions from deficient and control rats. These findings suggest the existence of a form of transaminase with little or no activity in the liver of deficient rats. The properties of the crude enzymes from deficient and control rats were indistinguishable by immunodiffusion, and the enzymes had the same subunit size and heat stability under the conditions tested. However, purified enzyme from deficient rat liver had a different specific activity and absorption spectrum from purified enzyme from normal liver.     

Reliability and minimal detectable change in scapulothoracic neuromuscular activity

Alterations in scapular muscle activity, including excess activation of the upper trapezius (UT) and onset latencies of the lower trapezius (LT) and serratus anterior (SA) muscles, are associated with abnormal scapular motion and shoulder impingement. Limited information exists on the reliability of neuromuscular activity to demonstrate the efficacy of interventions. The purpose of this study was to characterize the reproducibility of scapular muscle activity (mean activity, relative onset timing) over time and establish the minimal detectable change (MDC). Surface electromyography (sEMG) of the UT, LT, SA and anterior deltoid (AD) muscles in 16 adults were captured during an overhead lifting task in two sessions, one-week apart. sEMG data were also normalized to maximum isometric contraction and the relative onset and mean muscle activity during concentric and eccentric phases of the scapular muscles were calculated. Additionally, reliability of the absolute sEMG data during the lifting task and MVIC was evaluated. Both intrasession and intersession reliability of normalized and absolute mean scapular muscle activity, assessed with intraclass correlation coefficients (ICC), ranged from 0.62 to 0.99; MDC values were between 1.3% and 11.7% MVIC and 24 to 135 mV absolute sEMG. Reliability of sEMG during MVIC was ICC = 0.82–0.99, with the exception of intersession upper trapezius reliability (ICC = 0.36). Within session reliability of muscle onset times was ICC = 0.88–0.97, but between session reliability was lower with ICC = 0.43–0.73; MDC were between 39 and 237 ms. Small changes in scapular neuromuscular mean activity (>11.7% MVIC) can be interpreted as meaningful change, while change in muscle onset timing in light of specific processing parameters used in this study is more variable.     

Ultrastructural change of melanosomes associated with agouti pattern formation in mouse hair.

We have studied the structural alteration of melanosomes in the melanocytes of agouti mice whose genetic characteristic is to produce eumelanin and phaeomelanin alternately in a single hair bulb. Melanocytes of hair bulbs from 1 to 2 day old mice of the black phase were observed to contain rod-shaped melanosomes of the eumelanin type (eumelanosome). In the melanocytes of the hair bulbs from 4 to 6-day old skin, which exclusively contain phaeomelanin, spherical melanosomes (phaeomelanosomes) were seen. On the other hand, the mice of the transitional phase from black to yellow possessed melanocytes that contained both eumelanosomes and phaeomelanosomes within a single cell. This result indicates that the shift from the eumelanin formation to the phaeomelanin formation or vice versa in agouti hair occurs within a single melanocyte.We observed multivesicular bodies in both the agouti melanocytes of the yellow phase and the genotypically yellow melanocytes. These bodies are considered to be the precursor of the phaeomelanin-containing melanosome. They are sometimes observed to have continuity with E. R. suggesting that the melanosomes are derived from E. R. in the phaeomelanin-forming melanocytes.     

Presynaptic change associated with long-term potentiation in hippocampus

Long-term potentiation of the hippocampal response to repeated stimulation of rat entorhinal cortex occured concomitantly with a decrease in the excitability of presynaptic terminals. It is, therefore, possible that the long-term potentiation is caused, at least partly, by an enhancement of presynaptic efficacy.     

Exploring the minimal functional unit of the transporter associated with antigen processing

TAP, an ABC transporter in the ER membrane, provides antigenic peptides derived from proteasomal degradation to MHC class I molecules for inspection by cytotoxic T lymphocytes at the cell surface so as to trace malignant or infected cells. To investigate the minimal number of transmembrane segments (TMs) required for assembly of the TAP complex based on hydrophobicity algorithms and alignments with other ABC transporters we generated N-terminal truncation variants of human TAP1 and TAP2. As a result, a 6+6 TM core-TAP complex represents the minimal functional unit of the transporter, which is essential and sufficient for heterodimer assembly, peptide binding, and peptide translocation into the ER. The TM1 of both, core-TAP1 and core-TAP2 are critical for heterodimerization of the complex.