Bone microarchitecture and strength assessment in adults with osteogenesis imperfecta using HR-pQCT: normative comparison and challenges.

Data on bone microarchitecture in osteogenesis imperfecta (OI) are scarce. The aim of this cross-sectional study was to assess bone microarchitecture and strength in a large cohort of adults with OI using high-resolution peripheral quantitative computed tomography (HR-pQCT) and to evaluate challenges of using HR-pQCT in this cohort. Second-generation HR-pQCT scans were obtained at the distal radius and tibia in 118 men and women with Sillence OI type I, III, or IV using an extremity-length-dependent scan protocol. In total, 102 radius and 105 tibia scans of sufficient quality could be obtained, of which 11 radius scans (11%) and 14 tibia scans (13%) had a deviated axial scan angle as compared with axial angle data of 13 young women. In the scans without a deviated axial angle and compared with normative HR-pQCT data, Z-scores at the radius for trabecular bone mineral density (BMD), number, and separation were -1.6 ± 1.3, -2.5 ± 1.4, and -2.7 (IQR: 2.7), respectively. They were -1.4 ± 1.5 and -1.1 ± 1.2 for stiffness and failure load and between ±1 for trabecular thickness and cortical bone parameters. Z-scores were significantly lower for total and trabecular BMD, stiffness, failure load, and cortical area and thickness at the tibia. Additionally, local microarchitectural inhomogeneities were observed, most pronounced being trabecular void volumes. In the scans with a deviated axial angle, the proportion of Z-scores <-4 or >4 was significantly higher for trabecular BMD and separation (radius) or most total and trabecular bone parameters (tibia). To conclude, especially trabecular bone microarchitecture and bone strength were impaired in adults with OI. HR-pQCT may be used without challenges in most adults with OI, but approximately 12% of the scans may have a deviated axial angle in OI due to bone deformities or scan positioning limitations. Furthermore, standard HR-pQCT parameters may not always be reliable due to microarchitectural inhomogeneities nor fully reflect all inhomogeneities.

OI is a rare condition with large clinical heterogeneity. One of the major characteristics associated with OI is the increased fracture risk due to defects in bone structure and material. Data on the defects in bone structure at the micrometer level (i.e. bone microarchitecture) are scarce. Bone microarchitecture can be assessed noninvasively using HR-pQCT, but its use in OI has not extensively been described. Yet, potential challenges may arise related to among others the occurrence of short extremities and skeletal deformities in OI. We assessed bone microarchitecture and strength in 118 adults with OI types I, III, or IV using HR-pQCT with an extremity-length-dependent scan protocol. Additionally, we evaluated potential challenges of using HR-pQCT in this cohort. Our results demonstrated that predominantly trabecular microarchitecture­especially trabecular number and separation­and overall bone strength were impaired in adults with OI as compared with normative data. Furthermore, we observed various microarchitectural inhomogeneities, most pronounced being trabecular void volumes. Regarding applicability, HR-pQCT could be used without challenges in most adults with OI. However, deviations in scan region may potentially influence HR-pQCT parameters, and standard HR-pQCT analyses may not always give accurate results due to microarchitectural inhomogeneities nor fully reflect all microarchitectural inhomogeneities.

Prevalence of scoliosis and impaired pulmonary function in patients with type III osteogenesis imperfecta.

PURPOSE: Osteogenesis Imperfecta (OI) is a rare group of congenital genetic disorders that consists of a collagen synthesis defect. The most severe phenotype is type III OI. Characterized by progressive bone deformity, fragility and pulmonary impairment, causing significant morbidity and mortality. Also, multilevel spine deformities are observed, such as scoliosis. The literature on the pathophysiology of pulmonary impairment in relation to scoliosis in these patients is scarce and conflicting. This study aims to determine the prevalence of scoliosis and its relation to pulmonary function in type III OI patients. METHODS: This retrospective cohort study took place between April 2020 and November 2021. Forty-two patients with type III OI were included. Anterior-posterior spine radiographs were evaluated for scoliosis. Pulmonary function was assessed using spirometry and partial pressure of carbon dioxide. RESULTS: All 42 patients had scoliosis, with a mean curve of 66° (95% CI of range). Vital lung capacity was decreased, compared to a non-OI population (mean 1.57 L). This was correlated to the degree of scoliosis (st. ß - 0.40, P = 0.03), especially in increasing thoracic curves. Restrictive lung pathophysiology was shown in our study population with a mean FEV1/FVC ratio of 0.85. CONCLUSIONS: Increasing thoracic scoliosis was correlated with decreased vital lung capacity in our study population of type III OI patients. High FEV1/FVC ratios found in this study population show restrictive lung pathophysiology. Therefore, it is plausible that the pulmonary impairment found in type III OI patients is a combined issue, partly associated to scoliosis and partly intrinsic to OI.

[Chagas disease: screening tests evaluation in a blood military center, prevalence in the French Army]. / La maladie de Chagas: évaluation des tests de dépistage au centre de transfusion sanguine des armées, prévalence dans les armées.

Chagas disease is a major public health problem in Latin and Central America, 15 to 20 million people are affected and some 100 million is at risk of acquiring Chagas disease. Chagas disease starts to appear in amazonian area and french Guyana. Three kits: Elisa Novagnost (Dade Behring), BioElisa Chagas (Orgentec) et Elisa Cruzi (BioMérieux) were compared using performance panel. Sensibility, reproductibility and specificity (using 40 serum of blood donors who never went to an endemic area) were evaluated. Orgentec assay (recombinant antigens) and BioMérieux assay (whole-epimastigote antigens) performed better than Dade Behring assay. The latter was discarded from the study at this stage. Lack of sensibility seems due to the antigenic composition. Reproductibility and specificity are good for the other two tests. Mixtures of recombinants antigens increased specificity, but sensibility is better using mixtures of whole-epimastigote antigens. For routine blood donor screening both tests must be performed. A prevalence study was done during 11 months on 1570 serum of military blood donors. Despite of a low prevalence (less than 0.7 per thousand), the entire donation from donors who were in the endemic area (7.95% from our whole population) are screened for antibody against Trypanosoma cruzi, with these two assays.

[One case report of anti-JK1 antibody undetected on plasma sample]. / A propos d'un cas d'allo-immunisation anti-JK1 non dépisté sur plasma.

The sensitivity of the detection of irregular antibodies (DIA) is one of the fundamental bases of transfusion safety. Its implementation is specified in accordance with a very specific framework that allows the use of serum or plasma. The case reported here points out a failure to detect irregular antibodies in plasma sample. Thus a low intensity anti-JK1 antibody detected and identified in serum slipped through unnoticed in plasma. The difficulties to detect and identify this antibody, well-known as a deceptive and dangerous one, are being discussed in order to better assess the limitations of DIA.

[Blood transfusion security: one train may conceal another!]. / Sécurité transfusionnelle: un train peut en cacher un autre!

The discovery of antibodies with specificities that are directed toward antigens of high prevalence is a difficult situation to manage in emergency blood transfusion. The reactions they produce interfere with the identification of reactions due to other, clinically significant antibodies. We report a case which illustrates this problem in terms of transfusion safety and time to carry out the tests.

Osteogenesis imperfecta in childhood: MR imaging of basilar impression.

OBJECTIVE: To determine on radiographs the presence of Basilar Impression (BI) in children with Osteogenesis Imperfecta (OI). To confirm this sign and altered geometrical relationships of the craniocervical junction in course of time with magnetic resonance imaging (MRI). METHODS AND PATIENTS: In a cohort study of 130 patients with OI (OI type I: 85; OI type III: 21; OI type IV: 24) lateral radiographs of the skull and cervical spine were made in a standardised way. MRI scans were performed when BI was suspected based upon protrusion of the odontoid above Chamberlain's line. Intracranial abnormalities as well as the basal angle were described. Neurological examination was performed in patients with conclusive BI at MRI-scan. RESULTS AND DISCUSSION: In eight patients BI could be confirmed by MRI-scan. None of the children had or developed in time neurological symptoms or signs. Follow up of BI by MRI scans was done in seven patients (mean: 5 years; range: 2-6 years). No alteration of intracranial findings were seen at subsequent investigation, although in one child Chamberlain's line increased from 8 (first MRI) to 15 mm (last MRI). BI can be diagnosed by radiographs but in the extreme osteoporotic bone and altered anatomy of the craniocervical junction of children with OI MRI is preferable. As intracranial pathology can be demonstrated by MRI, also a relation can be laid to possible neurological symptoms and signs at clinical examination. CONCLUSION: In our cohort study no alteration of the intracranial contents was seen at subsequent MRI scans. Although anatomic deformations exist in BI, no neurological symptoms or signs were present in our study and no operative reconstruction had to be performed. Periodical MRI-scan has not been of influence on the clinical decision making process. At the moment we perform a MRI-scan if BI is suspected at lateral skull radiographs. The MRI images serve as reference findings to anticipate on possible future symptoms and signs of neurological deficit.

Multivariate analysis of determinants of bacterial contamination of whole-blood donations.

BACKGROUND AND OBJECTIVES: Introduction of bacteria into blood components at the collection stage seems to be a frequent occurrence. We therefore assessed determinants of bacterial contamination of whole-blood donations to gain insight into contamination mechanisms and direct prevention. MATERIALS AND METHODS: A cross-sectional study was carried out on donors accepted for whole-blood donation in four French blood banks. Each blood bank used its own two-stage procedure for phlebotomy site preparation. Contamination was identified by culturing two 15-ml samples (collected aseptically at the outset of donation) in a BacT/Alert 240 system. Determinants were assessed by logistic regression analysis. RESULTS: Bacterial contamination, mainly by skin flora, occurred in 76 (2.2%) out of 3385 donations. Significant determinants were as follows: the blood bank (odds ratio [OR] range = 3.0-5.6, P < 0.001); lack of repetition of scrub (OR = 2.7, P = 0.032); and donor age > 35 years (OR = 1.8, P = 0.036). CONCLUSION: Systematic scrub repetition should be implemented to reduce bacterial contamination by skin flora at the collection stage. Further research is required to clarify the role of different antiseptic agents and of donor age.

Efficacy of a new collection procedure for preventing bacterial contamination of whole-blood donations.

BACKGROUND: Transfusion-related bacterial contamination is a serious problem. The introduction of bacteria into donations at the collection stage seems frequent, despite well-conducted phlebotomy site preparation. Additional preventive measures are required. STUDY DESIGN AND METHODS: The aim of this study was to assess the potential efficacy of excluding the first 15 mL of blood to reduce the bacterial contamination of donations. A special device allowed the aseptic collection of two samples at the beginning of donation: S1 (first 15 mL) and S2 (next 15 mL). Bacteriologic cultures of S1 and S2 were performed by using an automated system. The procedure's efficacy was measured by the proportion of positive donations in S1 that were then negative in S2. RESULTS: S1 and/or S2 were positive in 76 (2.2%) of 3385 donations. In about three-fourths of the culture-positive donations, contamination was detected in the first 15-mL sample only. Gram-positive cocci accounted for 81 percent of species, gram-positive bacilli for 14 percent, and gram-negative bacilli for 5 percent. The new procedure would have prevented the introduction of bacteria in 55 donations, reducing to 0.6 percent the risk of contamination from the first 15 mL collected. CONCLUSION: Although the final effect on blood component bacterial contamination rates cannot be derived from the study, excluding the first 15 mL of blood may reduce the rate of bacterial contamination in donations.

Pyridinium cross-links in bone of patients with osteogenesis imperfecta: evidence of a normal intrafibrillar collagen packing.

The brittleness of bone in patients with osteogenesis imperfecta (OI) has been attributed to an aberrant collagen network. However, the role of collagen in the loss of tissue integrity has not been well established. To gain an insight into the biochemistry and structure of the collagen network, the cross-links hydroxylysylpyridinoline (HP) and lysylpyridinoline (LP) and the level of triple helical hydroxylysine (Hyl) were determined in bone of OI patients (types I, III, and IV) as well as controls. The amount of triple helical Hyl was increased in all patients. LP levels in OI were not significantly different; in contrast, the amount of HP (and as a consequence the HP/LP ratio and the total pyridinoline level) was significantly increased. There was no relationship between the sum of pyridinolines and the amount of triple helical Hyl, indicating that lysyl hydroxylation of the triple helix and the telopeptides are under separate control. Cross-linking is the result of a specific three-dimensional arrangement of collagens within the fibril; only molecules that are correctly aligned are able to form cross-links. Inasmuch as the total amount of pyridinoline cross-links in OI bone is similar to control bone, the packing geometry of intrafibrillar collagen molecules is not disturbed in OI. Consequently, the brittleness of bone is not caused by a disorganized intrafibrillar collagen packing and/or loss of cross-links. This is an unexpected finding, because mutant collagen molecules with a random distribution within the fibril are expected to result in disruptions of the alignment of neighboring collagen molecules. Pepsin digestion of OI bone revealed that collagen located at the surface of the fibril had lower cross-link levels compared with collagen located at the inside of the fibril, indicating that mutant molecules are not distributed randomly within the fibril but are located preferentially at the surface of the fibril.

Operative treatment of severe scoliosis in osteogenesis imperfecta: results of 20 patients after halo traction and posterior spondylodesis with instrumentation.

Correction and stabilisation of the scoliotic spine in osteogenesis imperfecta is difficult. The optimal technique has yet to be determined, since no large series in which a single procedure has been carried out by a single surgeon using a single protocol has yet been described. The charts of 20 patients with osteogenesis imperfecta who had undergone halo gravity traction (HGT) and a posterior spondylodesis with Cotrel-Dubousset (n = 18) or Harrington (n = 2) instrumentation were reviewed. No correction was made at the time of the surgical spondylodesis. The average follow-up was 4.8 years (range 2-10.5 years). The preoperative traction improved the Cobb angle of the scoliosis by 32% (from a mean of 78.5 degrees to a mean of 53.3 degrees) and improved the kyphosis by 24% (from a mean of 56.0 degrees to mean of 42.5 degrees). This correction deteriorated slightly at final follow-up, for both the scoliosis and the kyphosis (mean 57.6 degrees and 44.4 degrees respectively). Few complications were encountered during the HGT period. In 16 cases no complications occurred during the follow-up period. Ambulation and functional ability were upgraded for 7 of 20 patients.

Complications of the Bailey-Dubow elongating nail in osteogenesis imperfecta: 34 children with 110 nails.

The Bailey-Dubow nail, inserted in the femur or tibia of 34 children with osteogenesis imperfecta (OI), was studied retrospectively. Comparing the various groups of OI, no significant difference was found. Location of the nail (tibia or femur) did not influence the complication rate significantly. The reoperation rate was 29%, a rate comparable to that reported in earlier studies. The part of the nail located around the knee had a significantly higher migration rate (P = 0.005 at obturator ends and P = 0.007 at sleeve ends). Migration of the nail was the reason to reoperate in 50% of the patients. Better anchoring of the T-piece will substantially decrease the complication rate. In consideration of the different functional capacities of the OI population, the complications are likely related more to the hardware than to the patient.

Instrumentation for correction and fixation of scoliosis in fibrous dysplasia of the thoracolumbar spine.

A case report is presented in which correction of a thoracolumbar scoliosis, due to extensive fibrous dysplasia, is achieved using segmental spinal instrumentation with a 6-year follow-up. Pseudoarthrosis developed due to insufficient hook fixation at the sacrum.

[Consequences for labile blood products of leukocyte depletion by whole blood filtration using the Leucoflex LST1 in-line filter. Evaluation of the Leucoflex LST1 filter]. / Conséquences sur les PSL de la déleucocytation par filtration du sang total avec le filtre intégré Leucoflex LST1. Evaluation du filtre Leucoflex LST1.

The aim of this study is to evaluate the effects of whole blood filtration after a storage time of 20-24 hours at laboratory temperature using the in line filter Leucoflex LST1. The study concerns 49 blood donations in which we studied leukocyte depletion, proteins (IgG, IgA, IgM, haptoglobin, C3, C4), coagulation factors (fibrinogen, factors XII, XI, IX, VIII, V, proteins S and C, plasminogen, tPA, D-Dimers, PDF) at day 1, the parameters of conservation (ATP, 2-3 DPG, extra cellular potassium, haemolysis, pH) of red blood cell concentrates (RCCs) and bacteriological sterility at day 1 and 42. Despite a correct leukocyte depletion (mean depletion of 3.96 log), a 10 fold higher mean level of residual leukocytes/unit than with buffy coat poor RCC filtration (0.514.10(6) vs 0.051.10(6)) is observed. Moreover a lot of concentrates are not in accordance with French regulations (7/42 with more than 1.10(6) leukocytes/unit). The variation of the rates of IgG, IgA, IgM, haptoglobin, C4 and protein C is not significant. For the others there is a slight decrease with a mean level remaining in a physiological range. No sign of activation is noted. The sterility assays remain negative and the RCC conservation is not altered. In conclusion, even if the quality of the leukocyte depletion is not satisfactory in our study and has to be stated more precisely by multicenter studies, the whole blood filtration does not alter the quality of the derived components and allows us obtain RCC in a bigger volume and containing more haemoglobin than with the classical procedure after removing the buffy-coat [10].

An evaluation of a hospital-based drinking and driving prevention program.

For the past four years, Victoria Hospital has provided a drinking and driving prevention program: IMPACT - Impaired Minds Produced by Alcohol Cause Trauma. The program provides information to Grade 11 students about the potential "impact" of alcohol-related trauma on themselves, their family and their future. At the end of the program, students were asked to complete a short evaluative questionnaire; 74.2% completed the questionnaire. Of those responding, 97.5% agreed that the program increased their awareness of drinking and driving, and 79.4% agreed that the program would cause them to change their own behaviour. Determining whether or not increased knowledge and changed attitude in fact results in changed behaviour is beyond the scope of this study. Further longitudinal, quantitative evaluation of program effectiveness, based on traffic safety indices, is being undertaken.

Elevated risk of Helicobacter pylori infection in submarine crews.

In a prospective study designed to elucidate the route of transmission of Helicobacter pylori, the seroprevalence and incidence of Helicobacter pylori infection was determined in the following branches of the armed forces presumed to be at increased risk of acquiring transmissible diseases by the fecal-oral or oral-oral route: German submarine crews (n = 64, mean age 26.2 years) and regular officers of the French infantry (n = 51, mean age 26.5 years) who had served for a minimum of three years. The submarine crews were compared with air force staff (n = 74, mean age 23.7 years), and the French officers with French infantry recruits (n = 135, mean age 20.5 years) who started their service at the beginning of the study. The frequency of IgG and IgA antibody responses to the 120, 88, 86 and 82 kDa proteins was determined by the immunoblot method. The frequency of a positive antibody response was strongly dependent on age (p less than 0.001). When results were controlled for age by the logistic regression analysis, the submarine crews revealed significantly increased frequencies of the IgG and IgA responses compared to air force staff. The antibody responses of French officers and recruits were not significantly different. It is concluded that submarine crews serving during their missions in an overcrowded space with extremely limited sanitary facilities must be considered a high-risk group for Helicobacter pylori infection. These results strongly suggest person-to-person transmission of Helicobacter pylori, by either the oral-oral or the fecal-oral route.