Myeloid-associated differentiation antigens on stem cells and their progeny identified by monoclonal antibodies

Within the hematopoietic system, monoclonal antibodies reactive with antigenic determinants, expressed in a lineage- and stage-restricted fashion, can be used to map myeloid differentiation. We have generated a series of monoclonal antibodies that reacts with myeloid-associated determinants on committed myeloid stem cells and their progeny. Their reactivity with peripheral blood cells was identified by immunofluorescence assays, with bone marrow cells by fluorescence- activated cell sorting, and with committed hematopoietic progenitor cells by both cytotoxic assays and fluorescence-activated cell sorting. Antibody 1G10, which has previously been reported to react with cells of the granulocytic lineage and with a minor subset of mature monocytes, was shown to react with granulocyte-macrophage colony- forming units (CFU-GM). Three antibodies not previously characterized (T5A7, L4F3, L1B2) were shown to react with both granulocytic and monocytic cells and in fluorescence-activated cell sorting studies to detectably stain granulocytic cells at different stages of maturation. These three antibodies also react with CFU-GM, two (L4F3 and L1B2) reacting with all CFU-GM, while T5A7 reacts with only a portion of the day 7 CFU-GM. Antibody L4F3 also reacts with a portion of erythroid burst-forming units (BFU-E). In contrast, the previously reported antibody 5F1, which reacts with monocytic cells, nucleated erythroid cells, and platelets, was shown to react with erythroid colony-forming units (CFU-E). Potential applications of these antibodies to studies of normal and malignant hematopoiesis are discussed.     

Factors affecting mortality and reoperations in high-energy pelvic fractures

Aim

Factors affecting mortality during the first year following high-energy pelvic fractures has not been reported previously. Nor has surgical complications leading to reoperations been reported in a cohort with only high-energy pelvic trauma patients.

Objectives

The aim of this study was to report and analyse factors affecting outcome, in terms of mortality and reoperations, up to 1 year after the injury in patients with a traumatic pelvic ring injury due to a high-energy trauma.

Materials and methods

Data from the SweTrau (Swedish National Trauma Registry) on patients admitted to the Trauma Centre Karolinska in Stockholm, Sweden, were collected. Inclusion criteria were adults (age?≥?18), trauma with a high-energy mechanism, alive on arrival, Swedish personal identification number, reported pelvic fracture on CT scan. Patient records and radiographies were reviewed. The study period was 2011–2015 with 1-year follow-up time. Univariate and regression analysis on factors affecting mortality was performed. Risk of reoperation was analysed using univariate and case-by-case analysis.

Results

We included 385 cases with mean age 47.5?±?20.6 years (38% females): 317 pelvic fractures, 48 acetabular fractures and 20 combined injuries. Thirty-day mortality was 8% (30/385), and 1-year mortality was 9% (36/385). The main cause of death at 1 year was traumatic brain injury (14/36) followed by high age (>?70) with extensive comorbidities (8/36). Intentional fall from high altitude (OR 6, CI 2–17), GCS?<?8 (OR 12, CI 5–33) and age?>?70 (OR 17, CI 6–51) were factors predicting mortality. Thirty patients (22%, 30/134) were further reoperated due to hardware-related (n?=?18) or non-hardware-related complications (n?=?12). Hardware-related complications included: mal-placed screws (n?=?7), mal-placed plate (n?=?1), implant failure (n?=?6), or mechanical irritation from the implant (n?=?4). Non-hardware-related reasons for reoperations were: infection (n?=?10), skin necrosis (n?=?1), or THR due to post-traumatic osteoarthritis (n?=?1).

Conclusion

Non-survivors in our study died mainly because of traumatic brain injury or high age with extensive comorbidities. Most of the mortalities occurred early. Intentional injuries and especially intentional falls from high altitude had high mortality rate. Reoperation frequency was high, and several of the hardware-related complications could potentially have been avoided.

     

Medical students call for national standards in anatomical education

The diminishing number of hours dedicated to formal instruction in anatomy has led to a debate within medical education as to the level required for safe clinical practice. We provide a review of the current state of anatomical education in Australian medical schools and state the case for national standards. In light of the review presented, council members of the Australian Medical Students' Association voted to affirm that consideration should be given to developing undergraduate learning goals for anatomy, providing a codified medical student position on the teaching of anatomy in Australian medical schools. Crucially, the position states that time‐intensive methods of instruction such as dissection should be a rite of passage for medical students in the absence of evidence demonstrating the superiority of modern teaching methods. We believe the bodies with a vested interest in the quality of medical graduates, namely the Australian Medical Council, Medical Deans Australia & New Zealand, and the postgraduate colleges should collaborate and develop clear guidelines that make explicit the core knowledge of anatomy expected of medical graduates at each stage of their career with a view to safe clinical practice. In addition, Australian universities have a role to play in conducting further research into contemporary learning styles and the most efficacious methods of delivering anatomical education.     

Investigation of vascular compression of the trachea: the complementary roles of barium swallow and echocardiography

To determine the preferred investigation of congenital vascular compression of the trachea, preoperative investigation in 40 patients undergoing surgery 1981-91 was analysed. The importance of preoperative identification of detailed arterial anatomy in determining surgical technique was also assessed in 122 consecutive patients undergoing surgery 1952-91. Of the 40 patients (median age 5 months) seen 1981-91, barium swallow before referral suggested the diagnosis of vascular compression in 26 of 27 (96%). Angiography (1/3), bronchoscopy (0/6), and echocardiography (2/6) were generally unhelpful in diagnosing vascular compression before referral. Echocardiography was performed after referral in 18 consecutive patients since 1986 and the correct arterial anatomy was identified in 16 (88%); hyperinflation resulted in inadequate images in the two others. Barium swallow is the investigation of choice to screen for suspected vascular compression of the trachea; echocardiography at the referral centre can define the arterial anatomy in nearly all patients. Further investigation can be reserved for selected cases.     

Quantitative histologic study of the influence of spinal instrumentation on lumbar fusions: a canine model

Histomorphometric and microradiographic studies were performed on 28 beagle hounds 1 year of age, followed up for 6 months after an L5-L6 anterior and posterior spinal destabilization procedure--Group I (n = 7), destabilized surgical controls; Group II (n = 7), posterolateral bone grafting after destabilization; Group III (n = 7), Harrington rod instrumentation and posterolateral bone grafting after destabilization; and Group IV (n = 7), Luque instrumentation, and bone grafting after destabilization. Six months postoperatively, device-related osteoporosis occurred in spines treated with spinal instrumentation. Within the L5 vertebral body the mean trabecular width was less for the two groups with instrumentation (Groups III and IV) compared with the two groups without instrumentation (Groups I and II) (p less than 0.001). The bone formation rate [mm3/(mm3 x year)] x 10(3), which is based on the mean distance between sequenced fluorochrome labels, for Group I (destabilized, nonfused, noninstrumented dogs) was more than twice that of the other three groups, which were all equivalent (p less than 0.05). Clinical relevance: Stress shielding, or more correctly, device-related osteoporosis, probably can occur within vertebrae in response to rigid spinal instrumentation. However, the overall mechanical properties of vertebrae underlying spinal instrumentation are probably not at increased risk of fracture because the increase in cross-sectional area of the vertebra and incorporated fusion mass more than compensate for the loss of volumetric bone density.