Nonenzymatic Glycation and Degree of Mineralization Are Higher in Bone From Fractured Patients With Type 1 Diabetes Mellitus

Low‐energy fractures are frequent complications in type 1 diabetes mellitus patients (T1DM). Modifications of bone intrinsic composition might be a potential cause of fragility observed in diabetic subjects. Advanced glycation end products (AGEs) were found in numerous connective tissues from T1DM patients. However, whether AGEs are present at high levels in bone matrix from diabetic subjects is unknown. Moreover, whether elevated AGEs in the bone matrix impair mineralization has not been addressed in humans. The purposes of this study were 1) to determine whether bone matrix from fracturing and nonfracturing T1DM contained more AGEs than bone from healthy patients (CTL), and 2) to compare the degree of mineralization of bone and hardness between fracturing and nonfracturing T1DM versus CTL. We analyzed iliac crest bone biopsies from 5 fracturing T1DM patients, 5 nonfracturing T1DM patients, and 5 healthy subjects, all age‐ and sex‐matched. AGEs (pentosidine) in bone matrix was measured by high‐performance liquid chromatography separately in trabecular and cortical bone. The degree of mineralization of bone (DMB) was assessed by digitized microradiography, and mechanical properties by micro‐ and nanohardness tests. Trabecular bone from fracturing T1DM exhibited significantly higher levels of pentosidine than CTL (p = 0.04) and was more mineralized than nonfracturing T1DM (p = 0.04) and CTL (p = 0.04). Trabecular bone was not significantly different in pentosidine between nonfracturing T1DM and CTL. Cortical bone from nonfracturing T1DM was not significantly different from CTL. Positive correlations were found between HbA1c and pentosidine (r' = 0.79, p < 0.003) and between HbA1c and DMB (r' = 0.64, p < 0.02). Both modifications could lead to less flexible bone (reduced modulus of elasticity) and a tendency toward low‐energy fractures in T1DM patients. © 2015 American Society for Bone and Mineral Research.     

An unusual place to find a lost needle in laparoscopic surgery

Losing a needle during laparoscopic surgery is an uncommon but potentially challenging scenario for the surgeon. The prolonged operative time to search for a small retained foreign body such as a needle can cause clinical and medicolegal complications. As a result, it is considered a ‘never event’. This report describes a case of a lost needle during a laparoscopic prostatectomy, when a meticulous and systematic search for the foreign body was initiated and completed with the use of x-rays, only to find it in an unusual place.     

Blast cell colony assay for umbilical cord blood and adult bone marrow progenitors

We previously described candidate human blast cell colonies in culture of umbilical cord blood cells. However, their replating efficiencies were low, and we were unable to grow colonies from adult marrow cells. We report here a consistent method of growth and identification of human blast cell colonies that are supported by low serum culture and by delayed addition of medium conditioned by a T lymphoblast cell line, C5MJ. Nonadherent mononuclear cord blood and bone marrow cells were prepared by use of Ficoll-Paque and overnight adherence to plastic. Bone marrow cells were further enriched for progenitors by panning with monoclonal anti-My-10 antibody. Cells were plated in methylcellulose culture containing 2% fetal calf serum and supplemented with bovine serum albumin, lecithin, cholesterol, and transferrin. On day 14 of culture, concentrated C5MJ-conditioned medium was carefully added to each dish. Blast cell colonies consisting of 18 to 100 cells were detected on days 21 to 28. Forty percent to 75% of the blast cell colonies in individual samples yielded secondary colonies upon replating (positive colonies). The replating efficiency of the positive colonies ranged from 3% to 100%. The largest secondary colony contained 7,800 cells. In addition to single-lineage colonies, multilineage colonies revealing two to five lineage combinations were seen. These results suggest that human primitive progenitors are dormant in cell cycle and that they survive in the absence of colony-stimulating factors. Human blast cell colonies may provide a unique population of progenitors for studies of the early process of human hemopoiesis.     

High prevalence of nonsense, frame shift, and splice-site mutations in 16 patients with full-blown Wiskott-Aldrich syndrome

Wiskott-Aldrich syndrome (WAS) is a fully penetrant X-linked recessive disorder characterized by immunodeficiency, thrombocytopenia, and severe eczema. WAS is a life-threatening disease, with a poor quality of life and high mortality rate in childhood. The gene responsible for the disease has been localized to the proximal short arm of the X- chromosome and recently isolated through positional cloning and named WAS protein (WASP). We have characterized 17 WAS families. We have developed a rapid, nonradioactive screening protocol for identifying WASP gene alterations in genomic DNA. Our method allows simultaneous evaluation of single strand confirmation polymorphism and heteroduplex formation. We have identified 15 novel mutations that involve single basepair changes, or small insertions or deletions, all of which result in premature stop cordon, frame shift with secondary premature stop codon, or splice site defect. These studies document the considerable heterogeneity of the location of mutations in the WASP gene causing full-blown WAS and show the efficiency and rapidity of a screening approach for mutation identification in WAS that will be useful for carrier detection and prenatal diagnosis.     

Cleavage of supercoiled plasmid DNA by autoantibody Fab fragment: application of the flow linear dichroism technique.

A highly effective method consisting of two affinity chromatography steps and ion-exchange and gel-filtration chromatography steps was developed for purification of autoantibodies from human sera with DNA-hydrolyzing activity. Antibody Fab fragment, which had been purified 130-fold, was shown to catalyze plasmid DNA cleavage. The flow linear dichroism technique was used for quantitative and qualitative studying of supercoiled plasmid DNA cleavage by these autoantibodies in comparison with DNase I and EcoRI restriction endonuclease. The DNA autoantibody Fab fragment was shown to hydrolyze plasmid DNA by Mg(2+)-dependent single-strand multiple nicking of the substrate. Kinetic properties of the DNA autoantibody Fab fragment were evaluated from the flow linear dichroism and agarose gel electrophoresis data and revealed a high affinity (Kobsm = 43 nM) and considerable catalytic efficiency (kappcat/Kobsm = 0.32 min-1.nM-1) of the reaction.     

Molecular analysis of clonality and bcr rearrangements in Philadelphia chromosome-positive acute lymphoblastic leukemia

Philadelphia chromosome (Ph1)-positive chronic myelogenous leukemia (CML) patients consistently show a rearrangement in a 5.8-kilobase length of chromosome 22, referred to as the breakpoint cluster region (bcr). In Ph1-positive acute lymphoblastic leukemia (ALL), the breakpoint in chromosome 22 is more heterogeneous and, in some instances, does not occur within this region. In such cases the cell of origin of the neoplastic clone and the relationship of the disease to CML has remained obscure. We have analyzed the bcr rearrangement in the malignant cells from three patients who presented with Ph1-positive ALL and who in cytogenetic studies had shown evidence of variable involvement of myeloid cells in the Ph1-positive clone. Rearrangements in bcr typical of most cases of CML were detected in purified granulocyte preparations from two of the ALL patients (nos. 1 and 2) and in the blasts from patient 3 at the time of her terminal relapse. In the same analysis the simultaneously obtained granulocytes from patient 3, however, did not show any evidence of bcr rearrangement. Patient 3 was also heterozygous for the BamHI polymorphism in the X- linked hypoxanthine phosphoribosyltransferase (HPRT) gene, thus permitting a different method of clonal analysis based on methylation differences in active and inactive alleles. When DNA from her granulocytes that had shown no bcr rearrangement was hybridized to an HPRT probe, a pattern typical of a polyclonal population was seen. A similar pattern was exhibited by her marrow fibroblasts. In marked contrast, her simultaneously isolated blasts showed an unambiguous monoclonal pattern. These findings demonstrate the origin of the disease in the first two patients in a cell with myelopoietic as well as lymphopoietic potential and confirm the restricted lymphoid cell origin of the neoplastic clone in the third Ph1-positive ALL patient. Furthermore, they indicate that different target cells for transformation within the hematopoietic system may be affected by very similar bcr rearrangements.