Six new cases of CRB2-related syndrome and a review of clinical findings in 28 reported patients

The Crumbs homolog-2 (CRB2)-related syndrome (CRBS-RS) is a rarely encountered condition initially described as a triad comprising ventriculomegaly, Finnish nephrosis, and elevated alpha-fetoprotein levels in maternal serum and amniotic fluid. CRB2-related syndrome is caused by biallelic, pathogenic variants in the CRB2 gene. Recent reports of CRB2-RS have highlighted renal disease with persistent proteinuria and steroid-resistant nephrotic syndrome (SRNS). We report six new and review 28 reported patients with pathogenic variants in CRB2. We compare clinical features and variant information in CRB2 in patients with CRB2-RS and in those with isolated renal disease. The kidneys were the most frequently involved body system and 11 patients had only renal manifestations with SRNS or nephrotic syndrome. Central nervous system involvement was the next most common manifestation, followed by cardiac findings that included Scimitar syndrome. There was a significant clustering of pathogenic variants for CRB2-RS in exons 8 and 10, whereas pathogenic variants in exons 12 and 13 were associated with isolated renal disease. Further information is needed to determine optimal management but monitoring for renal and ocular complications should be considered.     

Lung function in children: a simple guide to performing and interpreting spirometry

Spirometry is the measurement of the volume and flow of air during expiration and inspiration. It is non-invasive and inexpensive and probably under-used in children. Whilst remaining a relatively simple test, it gives valuable information that can be used in the diagnosis and monitoring of respiratory conditions. Adequate spirometry requires good patient engagement, effort and technique. With practice, robust spirometry data can be collected in preschool children as young as 4 years of age. Increasing availability of portable spirometry equipment means that good quality data can be collected in a variety of clinical locations outside the lung function laboratory - even in the patient's own home. There are, however, a number of important considerations in both the performance and interpretation of spirometry. This review considers the equipment required, the basic techniques required and the essentials of interpretation of spirometry data.     

Growth factors and stromal support generate very efficient retroviral transduction of peripheral blood CD34+ cells from Gaucher patients

We have achieved high-efficiency gene transfer into nonmobilized peripheral blood (PB) CD34+ cells from patients with Gaucher's disease using a clinically acceptable retroviral supernatant transduction protocol. In our studies, bone marrow (BM) and PB CD34+ cells were transduced using a high titer (10(8) particles/mL) retroviral supernatant once a day for 4 consecutive days in the presence of interleukin-3 (IL-3), IL-6, and stem cell factor (SCF), with or without an irradiated allogeneic BM stromal layer. The growth factors alone resulted in 29% +/- 10% gene transfer of PB CD34+ clonogenic cells in contrast with 71% +/- 17% gene transfer efficiency using stroma with the growth factors; a 2.5-fold increase. The increase in gene transfer efficiency was less prominent when BM CD34+ cells were used (40% +/- 16% without and 57% +/- 8% with stroma, a 1.5-fold increase). The overall transduction efficiency of both PB and BM CD34+ cells was lower when the cells were transduced over a stromal cell layer without added growth factors. The combination of IL-3, IL-6, and SCF with stroma transduced 75% of primitive long-term culture initiating cells (PB LTC- ICs) in comparison with 34% of LTC-ICs when IL-3, IL-6, and SCF were used without stromal support. Using this clinically acceptable supernatant/cytokines/stroma transduction protocol, correction of the glucocerebrosidase (GC) deficiency in the progeny cells of PBLTC-ICs from Gaucher's-disease patients has been accomplished. Efficient transduction of the PB CD34+ cells using this transduction protocol may allow repeated delivery of "GC-corrected" hematopoietic stem and progenitor cells to Gaucher's-disease patients.     

Fluorine probes for investigating the mechanism of activation of indeno[1,2,3-cd]pyrene to a tumorigenic agent

Indeno[1,2,3-cd]pyrene (IP) is a non-alternant polycyclic aromatic hydrocarbon that has tumor-initiating activity on mouse skin and is carcinogenic in newborn mice and in rat lungs. Previous studies have shown that 8- and 9-hydroxyIP and IP-1,2-diol are major metabolites formed in vivo in mouse skin. 8-HydroxyIP-1,2-diol and 9-hydroxyIP-1,2-diol are also observed as in vivo metabolites of IP. Although 8-hydroxyIP had marginal tumor-initiating activity on mouse skin, IP-1,2-diol and its epoxide precursor, IP-1,2-oxide, had similar tumorigenic activity as IP. In the present study fluorine probes have been employed to investigate the contribution of metabolic activation at the 1,2 and 7-10 positions of IP. At a total initiating dose of 4.0 mumol, 2-fluoroIP induced skin tumors in 76% of the treated animals with an average of 3.9 tumors/mouse. At the same dose, IP induced a 72% incidence of tumor-bearing mice with 2.1 tumors/mouse. In contrast, 8,9-difluoroIP elicited a tumorigenic response in 40% of the treated animals with 0.6 tumors/animal. Five mice from each experimental group were killed at the conclusion of the initiation phase of the bioassay and DNA was isolated from the treated areas of skin. 32P-Postlabeling analysis of the hydrolyzed DNA indicated that IP forms one major detectable DNA adduct that migrates close to the origin. This adduct is absent in mice treated with 8,9-difluoroIP. In contrast, 2-fluoroIP forms one major adduct spot with different retention behavior as compared with the adduct formed from IP. DNA from mice treated topically with IP-1,2-diol and IP-1,2-oxide was subjected to 32P-postlabeling analysis. IP-1,2-diol forms one major DNA adduct spot with mobility similar to that observed for the IP-DNA adduct. IP-1,2-oxide displayed an intense pattern of DNA adducts centered around the location of the IP-DNA adduct. No adducts were detected which had mobility similar to that formed from 2-fluoroIP. These results are consistent with IP undergoing metabolic activation at positions 7-10 either alone or in conjunction with dihydrodiol formation at the 1,2 position.     

Development of the retinofugal projections in the embryonic and larval zebrafish (Brachydanio rerio)

Studies of the projection from the vertebrate retina have contributed significantly to current concepts of neural development. The zebrafish has recently become a favored system for the study of development in general and neural development in particular. Although the development of both the optic nerve and the retinotectal projection of the zebrafish has been described, the retinofugal projection in its entirety has not. This paper describes it and also addresses the issue of projectional exuberance: i. e., transient projections to targets that are not innervated in the adult. The retinofugal projection of embryonic and larval zebrafish (32 hours to 7 days post-fertilization) was labeled by intraocular injection of DiI (1,1′-dioctadecyl-3,3,3′,3′, tetramethylindocarbocyanine perchlorate) and then studied in wholemounts and sections. The first optic axons crossed the chiasm at 32 hours post-fertilization and projected in a straight line to reach the tectum at about 44 hours. At 48 hours, a few optic axons deviated along either the tract of the posterior commissure or the tract of the postoptic commissure. By 72 hours (about the time of hatching) optic axons arborized in ten distinct regions, termed arborization fields. At 6–7 days post-fertilization, the same ten arborization fields (nine contralateral, one bilater) were evident. Most of the arborization fields were located in the superficial neuropil and were not associated with morphologically identifiable clusters of somata. On the basis of various landmarks, the ten arborization fields are identified as precursors of retinorecipient nuclei previously described in other adult cypriniform fishes. The development was characterized by the nearly complete absence of any transient projections. Thus, the idea that axonal outgrowth is initially exuberant and trimmed back later is not supported by these results. © 1994 Wiley-Liss, Inc.