Bone Microarchitecture Phenotypes Identified in Older Adults Are Associated With Different Levels of Osteoporotic Fracture Risk

Prevalence of osteoporosis is more than 50% in older adults, yet current clinical methods for diagnosis that rely on areal bone mineral density (aBMD) fail to detect most individuals who have a fragility fracture. Bone fragility can manifest in different forms, and a “one-size-fits-all” approach to diagnosis and management of osteoporosis may not be suitable. High-resolution peripheral quantitative computed tomography (HR-pQCT) provides additive information by capturing information about volumetric density and microarchitecture, but interpretation is challenging because of the complex interactions between the numerous properties measured. In this study, we propose that there are common combinations of bone properties, referred to as phenotypes, that are predisposed to different levels of fracture risk. Using HR-pQCT data from a multinational cohort (n = 5873, 71% female) between 40 and 96 years of age, we employed fuzzy c-means clustering, an unsupervised machine-learning method, to identify phenotypes of bone microarchitecture. Three clusters were identified, and using partial correlation analysis of HR-pQCT parameters, we characterized the clusters as low density, low volume, and healthy bone phenotypes. Most males were associated with the healthy bone phenotype, whereas females were more often associated with the low volume or low density bone phenotypes. Each phenotype had a significantly different cumulative hazard of major osteoporotic fracture (MOF) and of any incident osteoporotic fracture (p < 0.05). After adjustment for covariates (cohort, sex, and age), the low density followed by the low volume phenotype had the highest association with MOF (hazard ratio = 2.96 and 2.35, respectively), and significant associations were maintained when additionally adjusted for femoral neck aBMD (hazard ratio = 1.69 and 1.90, respectively). Further, within each phenotype, different imaging biomarkers of fracture were identified. These findings suggest that osteoporotic fracture risk is associated with bone phenotypes that capture key features of bone deterioration that are not distinguishable by aBMD. © 2021 American Society for Bone and Mineral Research (ASBMR).     

Serum bone-gla protein after fracture

Serum bone Gamma-carboxyglutamic acid (bone-gla) protein (BGP), a marker of bone formation, was measured in serial blood samples drawn from 14 patients who had fractured at least one of their tibial or femoral diaphyses and from two other patients who had sustained major trauma without fracture but who had been immobilized. A total of 85 samples were taken and analyzed during the first three months after the fractures occurred. Serum BGP significantly increased and positively correlated with the time that had elapsed after the fracture, with an average twofold increase after two months. The fracture site and the duration of immobilization had no influence on the serum BGP levels. Serum BGP levels from the two non-fractured cases increased in the first two weeks with no subsequent consistent trend. These data suggest that serum BGP increases one to two months after a major fracture, possibly as a manifestation of bone repair. Further studies are required to determine the potential clinical value of serum BGP in the management of such patients.     

Direct and reverse dorsal metacarpal flaps.

We reviewed the anatomy of vascular systems used for both direct and reverse dorsal metacarpal flaps. The three-dimensional arrangement of the dorsal arterial network of the hand was examined. The collateral and terminal branches of this dorsal arterial network are described as a potential source of blood supply for composite flaps. Three types of dorsal-palmar anastomotic network were identified at the first and second metacarpal spaces, in the web space area. They could provide blood supply to reverse metacarpal flaps. Results of a series of 12 cases of reverse metacarpal flaps are given.     

Selective aflatoxin B1-induced sister chromatid exchanges and cytotoxicity in differentiating B and T lymphocytes in vivo

The purpose of this study was to assess the genotoxic and cytotoxic effects of the fungal metabolite aflatoxin B1 (AfB1) on the developing immune system of the chick embryo, a model in vivo system. Of particular interest was the assessment of AfB1 -mediated selective toxicity toward developing B lymphocytes as compared to T lymphocytes. In vivo bromodeoxyuridine (BrdU) labelling of DNA was used to detect the induction of sister chromatid exchanges (SCE) in lymphocytes and to assess the progression of these cells through successive cell cycles. Cytotoxicity was also assessed by studying the entrance and maintenance of cells in mitosis (mitotic index). Graded doses of AfB1 (1.09–17.4 μ/g embryo) were applied to chick embryos of 18 days of incubation (Dl). Embryos also received two doses of BrdU at 3 mg/200 μ (3 hr apart) to provide continuous labelling of B and T lymphocyte replicating DNA. B and T lymphocytes were harvested 20 hr post-AfB1/BrdU exposure from the bursa and thymus, respectively, and were processed for cytogenetic analyses. AfB1 induced dose-related increases in SCE in B lymphocytes; this induction was 6- to 8-fold that of controls at the higher doses tested, AfB1 -mediated induction of SCE in T cells was just 2-fold that of controls at the highest dose tested. AfB1 reduced the progression of B cells and to a lesser extent T ceels through successive rounds of replication. Furthermore, AfB1 dramatically reduced the mitotic index of B cells but not of T cells. These data indicate both selective genotoxicity and cytotoxicity of AfB1 toward B cells in the late stage embryo. © 1993 Wiley-Liss, Inc.     

Rapid detection of 17p11.2 rearrangements by FISH without cell culture (direct FISH,DFISH): a prospective study of 130 patients with inherited peripheral neuropathies

Charcot-Marie-Tooth (CMT) disease and hereditary neuropathy with pressure palsies (HNPP) are two frequent hereditary motor and sensory neuropathies. CMT is characterized by slowly progressive weakness and atrophy, primarily in peroneal and distal leg muscles. The most frequent form, CMT1A, is due, in most cases, to the duplication of a 1.5 Mb region on chromosome 17p11.2 containing the peripheral myelin protein 22 gene (PMP22). The phenotype seems to result from dosage of the PMP22 gene. This hypothesis is reinforced by the existence of HNPP, which is clinically characterized by various recurrent truncular palsies or sensory loss precipitated by minor trauma, which is caused by deletion of the same 1.5 Mb region in 17p11.2. In clinical practice, the detection of the duplication or the deletion in 17p11.2, which permits a positive diagnosis, is still performed by time consuming methods (Southern blot or various combinations of molecular tools). We developed a method for the rapid detection of 17p11.2 rearrangements, using "direct FISH" and PRINS analyses, which does not require cell culture. In a prospective study of 92 patients with CMT and 38 with suspected HNPP, we compared this new technique to classical strategies like Southern blot. The results demonstrate the high sensitivity and specificity of the new FISH technique for the diagnosis of CMT1A and HNPP. Moreover, because of its simplicity and rapidity, this technique provides a useful alternative to the molecular approaches that have been used to diagnose segmental aneusomies, especially in the case of duplications that often go undetected.     

Dra/AfaE adhesin of uropathogenic Dr/Afa+ Escherichia coli mediates mortality in pregnant rats

Escherichia coli bearing adhesins of the Dr/Afa family frequently causes urogenital infections during pregnancy in humans and has been associated with mortality in pregnant rats. Two components of the adhesin, Dra/AfaE and Dra/AfaD, considered virulence factors, are responsible for bacterial binding and internalization. We hypothesize that gestational mortality caused by Dr/Afa⁺ E. coli is mediated by one of these two proteins, Dra/AfaE or Dra/AfaD. In this study, using afaE and/or afaD mutants, we investigated the role of the afaE and afaD genes in the mortality of pregnant rats from intrauterine infection. Sprague-Dawley rats, on the 17th day of pregnancy, were infected with the E. coli afaE⁺ afaD and afaE afaD⁺ mutants. The clinical E. coli strain (afaE⁺ afaD⁺) and the afaE afaD double mutant were used as positive and negative controls, respectively. The mortality rate was evaluated 24 h after infection. The highest maternal mortality was observed in the group infected with the afaE⁺ afaD⁺ strain, followed by the group infected with the afaE⁺ afaD strain. The mortality was dose dependent. The afaE afaD double mutant did not cause maternal mortality, even with the highest infection dose. The in vivo studies corresponded with the invasion assay, where the afaE⁺ strains were the most invasive (afaE⁺ afaD strain > afaE⁺ afaD⁺ strain), while the afaE mutant strains (afaE afaD⁺ and afaE afaD strains) seemed to be noninvasive. This study shows for the first time that the afaE gene coding for the AfaE subunit of Dr/Afa adhesin is involved in the lethal outcome of gestational infection in rats. This lethal effect associated with AfaE correlates with the invasiveness of afaE⁺ E. coli strains in vitro.     

Compactibility study of calcium phosphate biomaterials

This study investigated the micromechanism responsible for the densification and consolidation of powders during dynamic compaction, an experimental process in which ceramic is formed without heating. Three calcium-deficient apatites (CDA: two powders and a fibrous compound) and a biphasic calcium phosphate (BCP) were studied to determine their aptitude (rheological and physical properties) for compactibility under various dynamic compaction pressures. Powders were investigated for their physicochemistry, particle size, and flow time, and compacts for their compaction rate, density, specific area, mechanical characteristics, and disintegration time. Powder particles showed different morphological features depending on the synthesis protocol used, specific area and rheological behaviour. Compacts were not obtained with BCP, regardless of the gas pressure used, whereas CDA produced compacts with good mechanical properties (high hardness and compression stress), particularly for the fibrous compound. The poor compressibility and compactibility of BCP powders were confirmed, whereas fibrous CDA powders showed good compactibility conducive to high-quality filling of biomaterials.     

Effects of Orally Administered Epidermal Growth Factor on Enteropathogenic Escherichia coli Infection in Rabbits

The increased intestinal absorption induced by epidermal growth factor (EGF) is associated with diffuse lengthening of brush border microvilli. The aim of this study was to examine the in vivo effects of oral administration of EGF during infection with enteropathogenic Escherichia coli. New Zealand White rabbits (4 weeks old) received orogastric EGF daily starting 3 days prior to infection with enteropathogenic E. coli RDEC-1 and were compared with sham-treated infected animals and uninfected controls. Weight gain, food intake, fecal E. coli, and stool consistency were assessed daily. On day 10, segments of jejunum, ileum, proximal, and distal colon were assessed for gram-negative bacterial colonization, disaccharidase activities, and epithelial ultrastructure. Effects of EGF on E. coli RDEC-1 proliferation were studied in vitro. E. coli RDEC-1 caused diarrhea and reduced weight gain. Seven days postinfection, the small and large intestines were colonized with numerous bacteria, brush border microvilli were disrupted, and maltase and sucrase activities were significantly reduced in the jejunum. Daily treatment with EGF prevented the occurrence of diarrhea and reduction of weight gain. These effects were associated with significant inhibition of E. coli colonization in the small and large intestine, improved jejunal maltase and sucrase activities and reduced microvillous injury. EGF did not affect the proliferation of E. coli in vitro. The findings suggest that EGF protects the gastrointestinal tract against colonization by enteropathogenic E. coli.     

Use of FTA gene guard filter paper for the storage and transportation of tumor cells for molecular testing.

CONTEXT: Efficient methods of storing tumor specimens for molecular testing are needed in the modern surgical pathology laboratory. The FTA Gene Guard system is a novel method for the collection and room temperature storage of blood samples for DNA testing. The method uses index card-sized filter papers that provide an ideal medium on which to store tumor specimens for DNA testing. OBJECTIVE: To determine whether FTA filter paper can be used in the surgical pathology laboratory to store tumor cells for DNA testing. DESIGN: Cell suspensions were prepared from 60 surgical specimens, and DNA was extracted either immediately or after storage on FTA paper. The DNA extracted by each method was tested by polymerase chain reaction (PCR) for the beta-globin and interferon gamma genes, and the results were compared. Fifteen lymph node specimens stored on FTA paper were then tested for immunoglobulin heavy chain (IgH) gene rearrangement by PCR, and these results were compared with those obtained for immediately extracted DNA.SETTING: University medical center. RESULTS: The DNA extracted from cells stored on FTA paper performed as well in the PCR as the freshly extracted DNA in nearly all cases (>95%). The results of tests for IgH gene rearrangements showed 100% concordance between the 2 methods of DNA extraction.Conclusion.-Cells from surgical specimens can be stored on FTA paper for extended lengths of time, and DNA can be extracted from these cells for PCR-based testing. FTA filter paper is a reliable medium for the storage and/or transport of tumor cells for PCR-based DNA analysis.