Clinical characteristics, genetic profile and short-term outcomes of children with primary hyperoxaluria type 2: a nationwide experience

BACKGROUND

Three types of primary hyperoxaluria (PH) are recognized. However, data on PH type 2 (PH2), caused by defects in the GRHPR gene, are limited.

METHODS

We reviewed the medical records of patients < 18 years of age with genetically-proven PH2 from seven centres across India to identify the age of onset, patterns of clinical presentation, short-term outcomes and genetic profile, and to determine if genotype-phenotype correlation exists.

RESULTS

We report 20 patients (all with nephrolithiasis or nephrocalcinosis) diagnosed to have PH2 at a median (IQR) age of 21.5 (7, 60) months. Consanguinity and family history of kidney stones were elicited in nine (45%) and eight (40%) patients, respectively. The median (IQR) serum creatinine at PH2 diagnosis was 0.45 (0.29, 0.56) mg/dL with the corresponding estimated glomerular filtration rate being 83 (60, 96) mL/1.73 m2/min. A mutational hotspot (c.494 G > A), rare in Caucasians, was identified in 12 (60%) patients. An intronic splice site variant (c.735-1G > A) was noted in five (25%) patients. Four (20%) patients required surgical intervention for stone removal. Major adverse kidney events (mortality or chronic kidney disease (CKD) stages 3-5) were noted in six (30%) patients at a median (IQR) follow-up of 12 (6, 27) months. Risk factors for CKD progression and genotype-phenotype correlation could not be established.

CONCLUSIONS

PH2 should no longer be considered an innocuous disease, but rather a potentially aggressive disease with early age of presentation, and possible rapid progression to CKD stages 3-5 in childhood in some patients. A mutational hotspot (c.494 G > A variant) was identified in 60% of cases, but needs further exploration to decipher the genotype-phenotype correlation.

Ultrasound Imaging of Renal Cysts in Children

Renal cysts can be focal or diffuse and unilateral or bilateral. In childhood, most renal cysts are due to hereditary diseases rather than simple cysts or acquired cystic diseases, unlike adults. Inherited cystic diseases can be ciliopathies due to a primary ciliary defect (as in polycystic kidney diseases and nephronophthisis). Acquired causes include obstructive cystic dysplasia, dyselectrolytemia, and acquired cysts in renal replacement therapy. The final diagnosis requires a multispecialty approach, including radiology, pathology, and genetics. Imaging is a very important component in treating patients with cystic renal diseases. This article discusses the ultrasound findings of cystic renal diseases in children, along with a brief discussion of other imaging modalities and a suggested ultrasound reporting format.

External Validation of the Newly Developed BETA-2 Scoring System for Pancreatic Islet Graft Function Assessment

BACKGROUND

BETA-2 score using a single fasting blood sample was developed to estimate beta-cell function after islet transplantation (ITx) and was validated internally by a high ITx volume center (Edmonton). The goal was to validate BETA-2 externally, in our center.

METHODS

Areas under receiver operating characteristic curves (AUROCs) were obtained to see if beta score or BETA-2 would better detect insulin independence and glucose intolerance.

RESULTS

We analyzed values from 48 mixed meal tolerance tests (MMTTs) in 4 ITx recipients with a long-term follow-up to 140 months (LT group) and from 54 MMTTs in 13 short-term group patients (ST group). AUROC for no need for insulin support was 0.776 (95% confidence interval [CI] 0.539-1, P = .02) and 0.922 (95% CI 0.848-0.996, P < .001) for beta score and 0.79 (95% CI 0.596-0.983, P = .003) and 0.941 (95% CI 0.86-1, P < .001) for BETA-2, in LT and ST groups, respectively, and did not differ significantly. In LT group BETA-2 score ≥ 13.03 predicted no need for insulin supplementation with sensitivity of 98%, specificity of 50%, positive predictive value (PPV) of 93%, and negative predictive value (NPV) of 75%. In ST group the optimal cutoff was ≥13.63 with sensitivity of 92% and specificity, PPV, and NPV 82% to 95%. For the detection of glucose intolerance BETA-2 cutoffs were <19.43 in LT group and <17.23 in ST group with sensitivity > 76% and specificity, PPV, and NPV > 80% in both groups.

CONCLUSION

BETA-2 score was successfully validated externally and is a practical tool allowing for frequent and reliable assessments of islet graft function based on a single fasting blood sample.

Intermittency and velocity fluctuations in hopper flows prone to clogging

We study experimentally the dynamics of granular media in a discharging hopper. In such flows, there often appears to be a critical outlet size D_{c} such that the flow never clogs for D>D_{c}. We report on the time-averaged velocity distributions, as well as temporal intermittency in the ensemble-averaged velocity of grains in a viewing window, for both D<D_{c} and D>D_{c}, near and far from the outlet. We characterize the velocity distributions by the standard deviation and the skewness of the distribution of vertical velocities. We propose a measure for intermittency based on the two-sample Kolmogorov-Smirnov D_{KS} statistic for the velocity distributions as a function of time. We find that there is no discontinuity or kink in these various measures as a function of hole size. This result supports the proposition that there is no well-defined D_{c} and that clogging is always possible. Furthermore, the intermittency time scale of the flow is set by the speed of the grains at the hopper exit. This latter finding is consistent with a model of clogging as the independent sampling for stable configurations at the exit with a rate set by the exiting grain speed [C. C. Thomas and D. J. Durian, Phys. Rev. Lett. 114, 178001 (2015)PRLTAO0031-900710.1103/PhysRevLett.114.178001].

Fraction of clogging configurations sampled by granular hopper flow

We measure the fraction F of flowing grain configurations that precede a clog, based on the average mass discharged between clogging events for various aperture geometries. By tilting the hopper, we demonstrate that F is a function of the hole area projected in the direction of the exiting grain velocity. By varying the length of slits, we demonstrate that grains clog in the same manner as if they were flowing out of a set of smaller independent circular openings. The collapsed data for F can be fit to a decay that is exponential in hole width raised to the power of the system dimensionality. This is consistent with a simple model in which individual grains near the hole have a large but constant probability to precede a clog. Such a picture implies that there is no sharp clogging transition, and that all hoppers have a nonzero probability to clog.

Geometry dependence of the clogging transition in tilted hoppers

We report the effects of system geometry on the clogging of granular material flowing out of flat-bottomed hoppers with variable aperture size D and with variable angle θ of tilt of the hopper away from horizontal. In general, larger tilt angles make the system more susceptible to clogging. To quantify this effect for a given θ, we measure the distribution of mass discharged between clogging events as a function of aperture size and extrapolate to the critical size at which the average mass diverges. By repeating for different angles, we map out a clogging phase diagram as a function of D and θ that demarcates the regimes of free flow (large D, small θ) and clogging (small D, large θ). We do this for both circular holes and long rectangular slits. Additionally, we measure four types of grain: smooth spheres (glass beads), compact angular grains (beach sand), disklike grains (lentils), and rodlike grains (rice). For circular apertures, the clogging phase diagram is found to be the same for all grain types. For narrow slit apertures and compact grains, the shape is also the same as for circular holes when expressed in terms of projected area of the aperture against the average flow direction. For lentils and rice discharged from slits, the behavior differs and may be due to alignment between grain and slit axes.

Elastic instabilities of polymer solutions in cross-channel flow

When polymer molecules pass near the hyperbolic point of a microchannel cross flow, they are strongly stretched. As the strain rate is varied at low Reynolds number (< 10(-2)), tracer and particle-tracking experiments show that molecular stretching produces two flow instabilities: one in which the velocity field becomes strongly asymmetric, and a second in which it fluctuates nonperiodically in time. The flow is strongly perturbed even far from the region of instability, and this phenomenon can be used to produce mixing.

Crystal structure of the phosphatidylinositol 3,4-bisphosphate-binding pleckstrin homology (PH) domain of tandem PH-domain-containing protein 1 (TAPP1): molecular basis of lipid specificity

Phosphatidylinositol 3,4,5-trisphosphate [PtdIns(3,4,5)P(3)] and its immediate breakdown product PtdIns(3,4)P(2) function as second messengers in growth factor- and insulin-induced signalling pathways. One of the ways that these 3-phosphoinositides are known to regulate downstream signalling events is by attracting proteins that possess specific PtdIns-binding pleckstrin homology (PH) domains to the plasma membrane. Many of these proteins, such as protein kinase B, phosphoinositide-dependent kinase 1 and the dual adaptor for phosphotyrosine and 3-phosphoinositides (DAPP1) interact with both PtdIns(3,4,5)P(3) and PtdIns(3,4)P(2) with similar affinity. Recently, a new PH-domain-containing protein, termed tandem PH-domain-containing protein (TAPP) 1, was described which is the first protein reported to bind PtdIns(3,4)P(2) specifically. Here we describe the crystal structure of the PtdIns(3,4)P(2)-binding PH domain of TAPP1 at 1.4 A (1 A=0.1 nm) resolution in complex with an ordered citrate molecule. The structure is similar to the known structure of the PH domain of DAPP1 around the D-3 and D-4 inositol-phosphate-binding sites. However, a glycine residue adjacent to the D-5 inositol-phosphate-binding site in DAPP1 is substituted for a larger alanine residue in TAPP1, which also induces a conformational change in the neighbouring residues. We show that mutation of this glycine to alanine in DAPP1 converts DAPP1 into a TAPP1-like PH domain that only interacts with PtdIns(3,4)P(2), whereas the alanine to glycine mutation in TAPP1 permits the TAPP1 PH domain to interact with PtdIns(3,4,5)P(3).

Caries detection accuracy by multiple clinicians and techniques

This study compared caries detection by multiple clinicians with the accuracy of detection with Caries Detector dye. Four clinicians rated the extent of caries on 100 extracted teeth. After dye application, visual assessment of residual dye was recorded for each specimen. This was repeated after the teeth were embedded in epoxy resin and sectioned. The results indicate that although reasonably accurate overall, clinicians often disagree whether caries is present. The use of a caries detector solution may be a valuable adjunct tool to correct caries diagnosis.

Investment strength as a function of time and temperature

OBJECTIVES

The purpose of this investigation was to evaluate and compare the compressive strength characteristics of selected investments and to determine if these change as a function of time and temperature after mixing.

METHODS

Two phosphate-bonded investments and one gypsum-bonded investment were selected and 288 cylindrical specimens were fabricated (n = 9). Baseline compressive strength values were determined for each material at room temperature and compressive strength measurements were made for all materials at 700 degrees C, and at 872 degrees C only for phosphate-bonded investments. Each material was tested at 2, 6, 12, and 24 h after mixing. Specimens were heated at 15 degrees C/min and heat soaked for 5 min in a burnout oven at the applicable testing temperature. They were transferred to a preheated chamber on an Instron testing machine and subjected to a compressive load at a crosshead speed of 2 mm/min until failure. The resulting strength data are presented in MN/m2.

RESULTS

The gypsum-bonded investment did not exhibit marked differences in strength as a function of either time or temperature. The phosphate-bonded investments, on the other hand, demonstrated considerable changes in compressive strength and differed in compressive strength characteristics at 700 degrees C and 872 degrees C respectively.

CONCLUSIONS

At elevated temperatures, all materials approximated peak strength 2 h after initial mixing. At room temperature, the phosphate-bonded investments in this study were not significantly stronger than the gypsum-bonded investment material. However, they exhibited increased compressive strength as a function of time and temperature that was considerably higher than that exhibited by the gypsum-bonded investments.

Meeting the challenge of consultation and collaboration: developing interactive teams

The roles of special educators as consultants and collaborators have long been established and supported. The rationale for these roles is also well documented. Many models--consultative, collaborative, and teaming--have been suggested in the literature; sometimes, these models exhibit similar goals, competencies, and processes. Because of intensified pressures to collaborate, successful implementation of collaborative and team efforts requires that special educators expand their roles as interactive professionals. The purpose of this article is to define and describe the consultation, collaboration, and teaming models that have been implemented, discuss their strengths and limitations, delineate how these models contribute to interactive teaming, outline key features of the interactive team, and provide some guiding principles for successful implementation.

Detection of medullary carcinoma of the thyroid with I-131 MIBG

Imaging with I-131 MIBG has proved useful for the detection of pheochromocytoma, neuroblastoma, and other neoplasms of neural crest origin. The authors present a case of a patient who was initially diagnosed as having follicular carcinoma of the thyroid in which I-131 MIBG played a key role in leading to the diagnosis of medullary carcinoma of the thyroid. Local and distant metastases were detected using I-131 MIBG imaging. Uptake of I-131 MIBG by medullary carcinoma of the thyroid has both diagnostic and therapeutic implications.

A survey of trainees and recently accredited specialists in occupational medicine in the United Kingdom

Information from a study group of doctors training or recently trained in occupational medicine was gathered using a self-administered questionnaire mailed to each subject's registered address. Of the 224 individuals identified from scrutiny of records held by the Faculty of Occupational Medicine, replies were received from 181 (81 per cent). Recruitment occurs in broadly equal proportions from general practice, general practice trainees, the hospital sector and the forces, with a wide diversity of experience among trainees. On average, trainees experience at least two industrial sectors during their training. There were disappointingly small numbers in part-time training.

Studies on osteoporosis. II. Effect of estrogens and fluoride on experimental osteoporosis. A preliminary report

Total skeletal calcium level was determined in female mice with the aid of whole body neutron activation analysis. Three months treatment with heparin produced significant osteoporosis in C3H/St(Ha) mice of 3--5 months of age. Treatment with a conjugated natural estrogen preparation (Premarin) prevented this phenomenon but high level fluoride in the drinking water failed to show preventive activity.

Studies on osteoporosis I. Experimental models. Effect of age, sex, genetic background, diet, steroid and heparin treatment on calcium metabolism of mice

C3H/St(Ha) and C57Bl/6(J) mice of both sexes and various ages were exposed to whole body neutron irradiation. The 49Ca generated (half life 8.8 minutes) was immediately determined in a whole body counter. Total body calcium content was calculated. It was assumed that 99% of this represented skeletal calcium. In females, significant decrease in calcium content occurred after 23 months of age. In C3H/St(Ha) mice, low calcium diet, heparin (500 i.u./Kg. b.i.d.) and prednisolone (50 mg/Kg) treatment accelerated calcium loss and produced significant decrease in 3 months. C57Bl/6(J) mice were less susceptible to the latter drugs.

Metastasizing basal cell carcinoma of the skin with myelophthisic anemia

A case report of a metastasizing basal cell carcinoma is presented, primary in the leg with regional inguinal lymph node metastasis, followed by extensive metastasis to skin and bone marrow with myelophthisic anemia and terminal splenohepatic and unilateral adrenal metastasis.