Histologic and Clinical Factors Associated with Kidney Outcomes in IgA Vasculitis Nephritis

BACKGROUND

Nephritis is a common manifestation of IgA vasculitis and is morphologically indistinguishable from IgA nephropathy. While MEST-C scores are predictive of kidney outcomes in IgA nephropathy, their value in IgA vasculitis nephritis has not been investigated in large multiethnic cohorts.

METHODS

Biopsies from 262 children and 99 adults with IgA vasculitis nephritis ( N =361) from 23 centers in North America, Europe, and Asia were independently scored by three pathologists. MEST-C scores were assessed for correlation with eGFR/proteinuria at biopsy. Because most patients ( N =309, 86%) received immunosuppression, risk factors for outcomes were evaluated in this group using latent class mixed models to identify classes of eGFR trajectories over a median follow-up of 2.7 years (interquartile range, 1.2-5.1). Clinical and histologic parameters associated with each class were determined using logistic regression.

RESULTS

M, E, T, and C scores were correlated with either eGFR or proteinuria at biopsy. Two classes were identified by latent class mixed model, one with initial improvement in eGFR followed by a late decline (class 1, N =91) and another with stable eGFR (class 2, N =218). Class 1 was associated with a higher risk of an established kidney outcome (time to ≥30% decline in eGFR or kidney failure; hazard ratio, 5.84; 95% confidence interval, 2.37 to 14.4). Among MEST-C scores, only E1 was associated with class 1 by multivariable analysis. Other factors associated with class 1 were age 18 years and younger, male sex, lower eGFR at biopsy, and extrarenal noncutaneous disease. Fibrous crescents without active changes were associated with class 2.

CONCLUSIONS

Kidney outcome in patients with biopsied IgA vasculitis nephritis treated with immunosuppression was determined by clinical risk factors and endocapillary hypercellularity (E1) and fibrous crescents, which are features that are not part of the International Study of Diseases of Children classification.

Autosomal dominant and autosomal recessive polycystic kidney disease: hypertension and secondary cardiovascular effect in children

Autosomal dominant (ADPKD) and autosomal recessive (ARPKD) polycystic kidney disease are the most widely known cystic kidney diseases. They are significantly different from each other in terms of genetics and clinical manifestations. Hypertension is one of the main symptoms in both diseases, but the age of onset and secondary cardiovascular complications are significantly different. Most ARPKD children are hypertensive in the first year of life and need high doses of hypertensive drugs. ADPKD patients with a very early onset of the disease (VEOADPKD) develop hypertension similarly to patients with ARPKD. Conversely, a significantly lower percentage of patients with classic forms of ADPKD develops hypertension during childhood, although probably more than originally thought. Data published in the past decades show that about 20%–30% of ADPKD children are hypertensive. Development of hypertension before 35 years of age is a known risk factor for more severe disease in adulthood. The consequences of hypertension on cardiac geometry and function are not well documented in ARPKD due to the rarity of the disease, the difficulties in collecting homogeneous data, and differences in the type of parameters evaluated in different studies. Overall, left ventricular hypertrophy (LVH) has been reported in 20%–30% of patients and does not always correlate with hypertension. Conversely, cardiac geometry and cardiac function are preserved in the vast majority of hypertensive ADPKD children, even in patients with faster decline of kidney function. This is probably related to delayed onset of hypertension in ADPKD, compared to ARPKD. Systematic screening of hypertension and monitoring secondary cardiovascular damage during childhood allows initiating and adapting antihypertensive treatment early in the course of the disease, and may limit disease burden later in adulthood.

Optical control of light polarization in heliconical cholesteric liquid crystals

We show here that light polarization of a beam propagating through a heliconical cholesteric cell can be controlled by tuning the Bragg resonance of the structure. We demonstrate that this control is achieved by varying either the low-frequency electric field or the intensity of a pump beam impinging on the sample. The study confirms the recently reported phenomenon of optical tuning of the heliconical cholesterics and opens the door for the development of simple and efficient polarization modulators controlled electrically or optically.

Parathyroid hormone and phosphate homeostasis in patients with Bartter and Gitelman syndrome: an international cross-sectional study

BACKGROUND

Small cohort studies have reported high parathyroid hormone (PTH) levels in patients with Bartter syndrome and lower serum phosphate levels have anecdotally been reported in patients with Gitelman syndrome. In this cross-sectional study, we assessed PTH and phosphate homeostasis in a large cohort of patients with salt-losing tubulopathies.

METHODS

Clinical and laboratory data of 589 patients with Bartter and Gitelman syndrome were provided by members of the European Rare Kidney Diseases Reference Network (ERKNet) and the European Society for Paediatric Nephrology (ESPN).

RESULTS

A total of 285 patients with Bartter syndrome and 304 patients with Gitelman syndrome were included for analysis. Patients with Bartter syndrome type I and II had the highest median PTH level (7.5 pmol/L) and 56% had hyperparathyroidism (PTH >7.0 pmol/L). Serum calcium was slightly lower in Bartter syndrome type I and II patients with hyperparathyroidism (2.42 versus 2.49 mmol/L; P = .038) compared to those with normal PTH levels and correlated inversely with PTH (rs -0.253; P = .009). Serum phosphate and urinary phosphate excretion did not correlate with PTH. Overall, 22% of patients had low serum phosphate levels (phosphate-standard deviation score < -2), with the highest prevalence in patients with Bartter syndrome type III (32%). Serum phosphate correlated with tubular maximum reabsorption of phosphate/glomerular filtration rate (TmP/GFR) (rs 0.699; P < .001), suggesting renal phosphate wasting.

CONCLUSIONS

Hyperparathyroidism is frequent in patients with Bartter syndrome type I and II. Low serum phosphate is observed in a significant number of patients with Bartter and Gitelman syndrome and appears associated with renal phosphate wasting.

Cardiac Abnormalities in Children with Autosomal Recessive Polycystic Kidney Disease

BACKGROUND

No previous study has defined the prevalence of cardiac geometric and mechanical function abnormalities through the analysis of advanced echocardiographic parameters in children with autosomal recessive polycystic kidney disease (ARPKD).

AIM

The purpose of this study was to evaluate cardiac geometry and function through advanced echocardiography in a well-characterized sample of pediatric patients with ARPKD.

METHODS

Standard echocardiograms were obtained in 27 children with ARPKD (0-18 years) and in 88 healthy children of similar age, gender distribution, and body build. Left ventricular (LV) hypertrophy was defined as LV mass > 45g/(m2.16 + 0.09) and cardiac remodeling was defined by age-adjusted relative wall thickness (RWT). Systolic function was assessed by ejection fraction, midwall fractional shortening (mFS), and global longitudinal (GLS) and circumferential strain (GCS).

RESULTS

Patients with ARPKD exhibited a higher LV mass index as compared to controls, and a more concentric LV geometry (both p < 0.001). Accordingly, the prevalence of abnormal LV geometry was significantly higher in ARPKD (33 vs. 0%; p < 0.005). No differences could be observed in the two groups for ejection fraction or GLS (both p = n.s.), while a significantly lower mFS (p < 0.05) as well as GCS (p < 0.001) could be observed. In the analysis of covariance, both LV mass index and RWT remained significantly higher in the ARPKD group, while mFS and GCS remained significantly lower (all p < 0.05). The prevalence of subclinical systolic dysfunction was significantly higher in patients with ARPKD as compared with control subjects (33 vs. 0%; p < 0.001).

CONCLUSIONS

Children with ARPKD show significantly impaired cardiac phenotype, characterized by high rates of LV abnormal geometry paired with systolic mechanical dysfunction.

Growth Hormone (GH) Therapy During the Transition Period: Should We Think About Early Retesting in Patients with Idiopathic and Isolated GH Deficiency?

To investigate growth hormone (GH) secretion at the transition age, retesting of all subjects who have undergone GH replacement therapy is recommended when linear growth and pubertal development are complete to distinguish between transitional and persistent GH deficiency (GHD). Early retesting of children with idiopathic and isolated GHD (i.e., before the achievement of final height and/or the adult pubertal stage) can avoid possible over-treatment. Here, we report data from our population with idiopathic and isolated GHD to encourage changes in the management and timing of retesting. We recruited 31 patients (19 males) with idiopathic GHD who received recombinant GH (rGH) for at least 2 years. All of the patients were retested at the transition age at least 3 months after rGH discontinuation. Permanent GHD was defined as a GH peak of <19 ng/mL after administration of growth hormone–releasing hormone (GHRH) + arginine as a provocative test. Permanent GHD was confirmed in only five of 31 patients (16.13%). None of these patients presented low serum insulin-like growth factor (IGF)-1 levels (<−2 standard deviation score (SDS)). Only one male patient with an IGF-1 serum level lower than −2 SDS showed a normal GH stimulation response, with a GH peak of 44.99 ng/mL. Few patients with idiopathic and isolated GHD demonstrated persistence of the deficit when retested at the transition age, suggesting that the timing of retesting should be anticipated to avoid overtreatment.

Inhibin B in healthy and cryptorchid boys

Background

Cryptorchidism, the most common male genital abnormality observed in paediatrics, might often be associated with long-term functional consequences and can even reoccur after a successful orchidopexy. Serum markers that identify cryptorchid boys with gonadal dysfunction early should be useful in a decision-making process. Inhibin B, produced during all of childhood but altered in cryptorchid subjects, appears strictly related to Sertoli cells, and its levels directly reflect the status of the testis germinative epithelium. Unfortunately, its precise roles in bilateral and unilateral cryptorchidism are still debated and being unravelled. Herein, we report the most current knowledge about inhibin B in both healthy boys and those with cryptorchidism to discuss and clarify its potential clinical applications.

Discussion

Inhibin B represents a simple and repeatable serum marker and it seems to well asses the presence and function of the testicular tissue. Testicular tissue in prepubertal age is largely made up of Sertoli cells; inhibin B, coming from working Sertoli cells, allows to indirectly evaluate their function. Besides, inhibin B is produced throughout childhood, even before puberty, in contrast with central hormones, and it is not influenced by androgens during puberty, in contrast with other testicular hormones. Although further studies are needed, low levels of inhibin B have been related with low testicular score and/or with consistent alterations of testicular parameters at histological examination. This means that inhibin B could be an indirect marker of testicular functions that could even replace testicular biopsies, but current data are inconsistent to confirm this potential role of inhibin B in cryptorchidism.

Conclusion

Inhibin B represents an effective candidate for early identification of testicular dysfunction after orchidopexy for cryptorchidism. Unfortunately, current data cannot exactly clarify the real role of inhibin B as a predictor of future testicular function in cryptorchidism and future long-term follow-up studies, with repeated inhibin B checks both in cryptorchid and in formerly cryptorchid children and adolescents, will permit to assess if previous normal levels of inhibin B would match with future normal pubertal development and fertility potential.

Report of a Novel SHOX Missense Variant in a Boy With Short Stature and His Mother With Leri-Weill Dyschondrosteosis

Heterozygous mutations in the SHOX gene or in the upstream and downstream enhancer elements are associated with 2-22% of cases of idiopathic short stature (OMIM #300582) and with 60% of cases of Leri-Weill dyschondrosteosis (OMIM #127300) with which female subjects are generally more severely affected. Approximately 80-90% of SHOX pathogenic variants are deletions or duplications, and the remaining 10-20% are point mutations that primarily give rise to missense variants. The clinical interpretation of novel variants, particularly missense variants, can be challenging and can remain of uncertain significance. Here, we describe a novel missense variant (c.1044 G>T, p.Arg118Met) in a Moroccan boy with a disproportionately short stature and without any radiological traits or bone deformities and in his mother, who had a disproportionately short stature and a Madelung deformity. This variant has not been reported to date in the updated SHOX allelic variant or Human Gene Mutation Databases nor is it listed as a polymorphism in the ExAC browser, dbSNP, or 1000G. This mutation was predicted to be deleterious by three different bioinformatics tools since it modifies an amino acid in a highly conserved DNA-binding domain of the SHOX protein. Based on this evidence, the patient was treated with recombinant human growth hormone.

The Effect of Bisphenol A on Puberty: A Critical Review of the Medical Literature

Many scientific studies have revealed a trend towards an earlier onset of puberty and have disclosed an increasing number of children that display precocious puberty. As an explanation, some authors have considered the global socio-economic improvement across different populations, and other authors have considered the action of endocrine disrupting chemicals (EDCs). Among these, bisphenol A (BPA), an aromatic compound largely used worldwide as a precursor of some plastics and chemical additives, is well known for its molecular oestrogen-like and obesogenic actions. We reviewed the medical literature of the previous 20 years that examined associations between BPA exposure and the age of puberty in humans, considering only those referring to clinical or epidemiological data. Of 19 studies, only 7 showed a correlation between BPA and puberty. In particular, the possible disruptive role of BPA on puberty may be seen in those with central precocious puberty or isolated premature breast development aged 2 months to 4 years old, even if the mechanism is undefined. Some studies also found a close relationship between urinary BPA, body weight, and early puberty, which can be explained by the obesogenic effect of BPA itself. The currently available data do not allow establishment of a clear role for BPA in pubertal development because of the conflicting results among all clinical and epidemiological studies examined. Further research is needed to fully understand the potential role of exposure to EDCs and their adverse endocrine health outcomes.

Light controlled phase shifter for optofluidics

We report the light-induced control of optical phase shift by a liquid crystal cell made with LiNbO3:Fe crystals as substrates. We show that a phase shift of a few πs can be easily reached for two orthogonal polarizations due to liquid crystal reorientation driven by the photovoltaic electric field originated in the substrates. This effect is exploited to get all-optical switching with a contrast of about 80%, by 2 s pump pulse.

Optical nonlinearity in the nematic phase of bent-core mesogens

Nonlinear optical response of the cybotactic nematic phase of a bent-core mesogen has been investigated for the first time through self-phase modulation induced by a Gaussian beam. The material exhibits a high nonlinear response achieving a nonlinear index n(2)≈5×10(-5)  cm(2)/W and an unconventional behavior characterized by two different regimes. While the high-intensity regime can be easily explained in terms of a thermal indexing effect, the low-intensity regime is metastable and characterized by an unusual dependence on the irradiation energy. It is suggested that a change of the director configuration, possibly due to a light-induced modification of surface anchoring, is responsible for the observed behavior.

True Precocious Puberty Following Treatment of a Leydig Cell Tumor: Two Case Reports and Literature Review

Leydig cell testicular tumors are a rare cause of precocious pseudopuberty in boys. Surgery is the main therapy and shows good overall prognosis. The physical signs of precocious puberty are expected to disappear shortly after surgical removal of the mass. We report two children, 7.5 and 7.7 year-old boys, who underwent testis-sparing surgery for a Leydig cell testicular tumor causing precocious pseudopuberty. During follow-up, after an immediate clinical and laboratory regression, both boys presented signs of precocious puberty and ultimately developed central precocious puberty. They were successfully treated with gonadotropin-releasing hormone (GnRH) analogs. Only six other cases have been described regarding the development of central precocious puberty after successful treatment of a Leydig cell tumor causing precocious pseudopuberty. Gonadotropin-dependent precocious puberty should be considered in children treated for a Leydig cell tumor presenting persistent or recurrent physical signs of puberty activation. In such cases, therapy with GnRH analogs appears to be the most effective medical treatment.

Role of space charges on light-induced effects in nematic liquid crystals doped by methyl red

We show that both the extraordinarily large nonlinear response and the light-induced permanent reorientation in liquid crystals doped by the azo dye methyl red originates from the same phenomenon of modification of the charge density on the irradiated surface. The demonstration is done by applying ac voltage to the samples, showing that in this case no permanent anchoring is possible. The measurements confirm the role of photoisomerization that gives a transient contribution to the actual reorientation process only in the high dose regime. This result allows us to draw a picture for light-induced effects that might be applied to a large class of compounds.

First-order optical Freedericksz transition in a dye-doped nematic liquid crystal

A first-order optical Freedericksz transition in a nematic liquid crystal doped by a small quantity of a dichroic dye with negative dichroism is observed. The initial homeotropic state corresponds to maximum absorption for the linearly polarized incident beam, while reorientation reduces absorption increasing the optical torque: this process produces the positive feedback leading to the observed bistable behavior.

Optical trapping induced by reorientational nonlocal effects in nematic liquid crystals

We report a detailed analysis of optical trapping of low index particles in liquid crystals under experimental conditions that prevent the effect of conventional trapping originated by optical gradient forces. The observation of stable, long-range trapping shows that this phenomenon in liquid crystals is regulated by a completely different mechanism than in isotropic media. In particular, the role of the nonlocality of optical reorientation is highlighted by showing the dependence of the trapping force on the size of the reoriented area. A model based on the actual form of the Gaussian focused beam impinging on the liquid-crystalline medium in the trapping experiment is also reported, with good agreement with experimental data.

Surface-induced nonlinearities of liquid crystals driven by an electric field

We report the study of the effect of a static electric field on the huge optical nonlinearity of methyl-red doped nematic liquid crystals. Experimental data are well fitted using a theoretical model that takes into account the modulation of the surface charge density due to the impinging light beam. It is demonstrated that the optical nonlinearity can be varied by orders of magnitude with application of a low voltage below the threshold of the Fredericks transition. These results confirm the previously proposed model of surface induced nonlinear effects.

Phenomenological model for the optically induced easy direction

We present a phenomenological model to interprete the optically induced easy direction in a nematic cell in the slab approximation. One of the surfaces of the sample is supposed to give strong anchoring, whereas the other, covered with photosensible material, very weak anchoring. We assume that a surface nematic molecule is submitted to a potential connected with its interaction with the surface easy direction, with the surface nematic field, and with the optical induced anisotropy. The case in which the coupling with the nematic order in the bulk is important is considered too. A differential equation for the time evolution of the surface director is proposed, in which the viscous torque is balanced by the torque related to the surface fields. We show that our theoretical predictions are in agreement with experimental data on the optical induced surface orientation. The dependence of the anchoring energy strength on the irradiation time for dye-doped liquid crystals is also investigated.

Colossal optical nonlinearity induced by a low frequency external electric field in dye-doped liquid crystals

We report on the effects of a low-frequency electric field on the optical nonlinear response of thin dye-doped liquid crystal cells. Experimental data show that the external field allows reaching extremely high values of the optical nonlinearity without any critical control of the cell interfaces. A qualitative interpretation of the collected data, based on the light-induced modulation of the bulk voltage through surface modifications, is proposed.

Light-induced molecular adsorption and reorientation at polyvinylcinnamate-fluorinated/liquid-crystal interface

We have carried out a detailed experimental study, by means of x-ray reflectometry (XRR) and half-leaky guided mode (HLGM) optical characterization, of the light-induced molecular adsorption and reorientation at the polyvinylcinnamate-fluorinated (PVCN-F)/liquid-crystal (LC) interface of a LC cell doped with the azo-dye methyl red (MR). The XRR data allowed characterizing the microscopic structure of the adsorbed dye layer both before irradiation (dark adsorption) and after irradiation (light-induced adsorption). The HLGM optical characterization has made possible the experimental determination of the nematic director profile in the LC cell and evaluation of the effects of light-induced adsorption on the LC anchoring conditions. The experimental findings have confirmed the formation of a dark-adsorbed layer and are in agreement with the absorption model previously proposed to account for the complex phenomenology related to light-induced anchoring and reorientation in dye-doped liquid crystals.

Surface reorientation induced by short light pulses in doped liquid crystals

Fast surface reorientation induced by a single 4-ns low-energy laser pulse in dye-doped liquid crystals is reported. The reorientation is due to light-induced modification of the surface anisotropy, which affects the liquid crystal's director through the appearance of a preferred direction on the irradiated surface. The detected signals can be interpreted as being the result of light-induced desorption and adsorption of dye molecules.

On the origin of the huge nonlinear response of dye-doped liquid crystals

We report the results of an investigation carried on Methyl Red-doped nematic liquid crystals with the aim of studying the basic mechanism of the extraordinarily large nonlinear response recently reported. We show that the experimental data can be explained as due to light-induced modifications of the anchoring conditions leading to director reorientation on the irradiated surface, which in turn gives rise to a bulk reorientation through the cell. We have called this phenomenon SINE (Surface Induced Nonlinear Effect) to remind that it occurs "without" (= sine in latin language) a direct optical or electric torque on the director in the bulk.

Fast optical recording in dye-doped liquid crystals

Light-induced director reorientation in dye-doped nematic liquid crystals was recently reported to be an efficient method of writing permanent holographic gratings with high sensitivity [Phys. Rev. Lett. 82, 1855 (1999)]. We report the achievement of stable director reorientation in the same materials by means of a single 4-ns pulse of the second harmonic of a Nd:YAG laser. Fast recording of high-resolution holographic gratings (more than 500 lines/mm) can be obtained with an energy density as low as 7x10(-3)J /cm(2) .

Immunosuppressive and anti-inflammatory effects of methanolic extract and the polyacetylene isolated from Bidens pilosa L

The immunomodulatory effect of the methanolic extract obtained from dried leaves of Bidens pilosa L. (Asteraceae) and the polyacetylene 2-O-beta-D-glucosyltrideca-11 E-en-3,5,7,9-tetrayn-1,2-diol (PA-1) isolated from it was investigated. The extract inhibited the proliferative response in two in vitro models: human lymphocytes stimulated by 5 microg ml(-1) phytohemagglutinin (PHA) or to 100 nM 12-O-tetradecanoyl phorbol-13-acetate (TPA) plus 0.15 microM ionomycin and murine lymphocytes stimulated by 5 microg ml(-1) concanavalin A (Con A) or in the mixed leukocyte reaction (IC50 = 12.5 to 25 microg ml(-1)). PA-1 was 10-told more potent than the original extract in blocking both human and murine lymphocyte proliferation (IC50 = 1.25 to 2.5 microg ml(-1)). In mice, the intraperitoneal (i.p.) administration of methanolic extract of B. pilosa significantly reduced the size of the popliteal lymph node (PLN) after the inflammation induced by zymosan. One week after the injection of zymosan (150 microg) in the foot pad, PLN weighed 4.6 +/- 0.6 mg in comparison with 0.5 +/- 0.07 mg of the contralateral non-inflamed foot pad. The i.p. treatment with 10 mg extract from day 2 to day 6 after zymosan injection reduced the PLN weight to 1.8 +/- 0.3 mg. The data suggest an immunosuppressive activity of components of B. pilosa that may explain its popularly perceived anti-inflammatory effect.

Skin movement artefact assessment and compensation in the estimation of knee-joint kinematics

In three dimensional (3-D) human movement analysis using close-range photogrammetry, surface marker clusters deform and rigidly move relative to the underlying bone. This introduces an important artefact (skin movement artefact) which propagates to bone position and orientation and joint kinematics estimates. This occurs to the extent that those joint attitude components that undergo small variations result in totally unreliable values. This paper presents an experimental and analytical procedure, to be included in a subject-specific movement analysis protocol, which allows for the assessment of skin movement artefacts and, based on this knowledge, for their compensation. The effectiveness of this procedure was verified with reference to knee-joint kinematics and to the artefacts caused by the hip movements on markers located on the thigh surface. Quantitative validation was achieved through experimental paradigms whereby prior reliable information on the target joint kinematics was available. When position and orientation of bones were determined during the execution of a motor task, using a least-squares optimal estimator, but the rigid artefactual marker cluster movement was not dealt with, then knee joint translations and rotations were affected by root mean square errors (r.m.s.) up to 14 mm and 6 degrees, respectively. When the rigid artefactual movement was also compensated for, then r.m.s errors were reduced to less than 4 mm and 3 degrees, respectively. In addition, errors originally strongly correlated with hip rotations, after compensation, lost this correlation.

Macro serum CK-BB in a woman with severe primary hypothyroidism

We report the case of a woman with severe hypothyroidism and without concomitant myocardial damage, in whom elevated CK-MB values were measured by radioimmunological and enzymatic methods before and after thyroid replacement therapy. The patient's CK-MB activity was shown to be actually due to an atypical CK band between CK-MM and CK-MB (also termed "macro CK" or "idiopathic serum CK-BB").

[Interaction of the genes of progressive muscular dystrophy (PMD) and blood groups (ABO)]

Verification of the hypothesis that the inheritance of the Progressive Muscular Dystrophies (PMD) may involve dispersed genes, throiugh the study of a sample of 105 patients revealed that 82% of the Duchenne type belong to blood group O, while 79% of the limb-girdle type belong to group A. The fact that the Duchenne gene is sex-linked while the ABO locus is on chromosome 9 confirms the "dispersed genes" hypothesis, with important implications for further research, for genetic counselin and possibly for prevention.