First-time anterior cruciate ligament injury in adolescent female elite athletes: a prospective cohort study to identify modifiable risk factors.

PURPOSE: To identify modifiable biomechanical and neuromuscular anterior cruciate ligament (ACL) injury risk factors for first-time ACL injury in adolescent female elite football and team handball players. METHODS: Adolescent female elite football and handball players with no previous ACL injury participated in the present study. At baseline, players were tested during side-cutting manoeuvres performed in a 3-dimensional motion analysis laboratory with concomitant electromyography (EMG) measurements. Maximal isometric lower limb muscle strength was assessed by handheld dynamometry. Players were prospectively followed for 2 years after baseline testing, and all magnetic resonance imaging (MRI) verified ACL injuries were registered. The effect of 16 risk factor candidates on the relative risk (RR) of ACL injury was estimated using Poisson regression analysis. RESULTS: Ninety players (age 16.9 ± 1.2 years) were included in the analyses. Nine first-time ACL injuries (injury incidence 10.0% (95% confidence interval (CI) 5.4-18.6%)) were registered during the 2-year follow-up period. Four risk factor candidates were significantly associated with the risk of ACL injury: (1) hip flexion angle at initial contact (IC) [RR 0.56, 95% confidence interval (CI) 0.34-0.92], (2) internal knee rotation angle at IC [RR 1.13, 95% CI 1.08-1.19], (3) semitendinosus EMG activity 50 ms prior to IC [RR: 0.62, 95% CI 0.43-0.89], and (4) external hip rotator strength [RR: 0.77, 95% CI 0.66-0.89]. CONCLUSION: Four distinct ACL injury risk factors related to the side-cutting manoeuvre were identified in a population of adolescent female elite football and team handball players with no previous ACL injury. As ACL injury typically occur during side-cutting, intervention programmes to modify these risk factors pose a promising strategy for ACL injury prevention in adolescent female elite football and team handball. LEVEL OF EVIDENCE: II.

Control of collagen gel mechanical properties through manipulation of gelation conditions near the sol-gel transition.

The ability to control the mechanical properties of cell culture environments is known to influence cell morphology, motility, invasion and differentiation. The present work shows that it is possible to control the mechanical properties of collagen gels by manipulating gelation conditions near the sol gel transition. This manipulation is accomplished by performing gelation in two stages at different temperatures. The mechanical properties of the gel are found to be strongly dependent on the duration and temperature of the first stage. In the second stage the system is quickly depleted of free collagen which self assembles into a highly branched network characteristic of gelation at the higher temperature (37 °C). An important aspect of the present work is the use of advanced rheometric techniques to assess the transition point between viscoelastic liquid and viscoelastic solid behaviour which occurs upon establishment of a sample spanning network at the gel point. The gel time at the stage I temperature is found to indicate the minimum time that the gelling collagen sample must spend under stage I conditions before the two stage gelation procedure generates an enhancement of mechanical properties. Further, the Fractional Maxwell Model is found to provide an excellent description of the time-dependent mechanical properties of the mature collagen gels.

The effect of intensified nonverbal facilitation of swallowing on dysphagia after severe acquired brain injury: A randomised controlled pilot study.

BACKGROUND: There is little high-level evidence for the effect of the nonverbal facilitation of swallowing on swallowing ability in the subacute stage of rehabilitation following severe acquired brain injury (ABI). OBJECTIVE: To pilot test a randomised controlled trial to determine the effect of an intensification of the nonverbal facilitation of swallowing on dysphagia. METHODS: Ten patients with severe ABI and dysphagia were randomised into two groups at a highly specialised neurorehabilitation clinic.The intervention group received an intensification of the nonverbal facilitation of swallowing and the control group received basic care of the face and mouth in addition to treatment as usual for two sessions of 20 minutes per day for three weeks.Outcomes were Functional Oral Intake Scale (FOIS), Penetration Aspiration Scale (PAS), and electrophysiological swallowing specific parameters (EMBI). RESULTS: The intensified intervention was feasible. PAS and FOIS scores improved in both groups, with no differences between groups. The swallowing specific parameters reflected clinically observed changes in swallowing. CONCLUSIONS: PAS and FOIS are feasible instruments to measure dysphagia. It is possible and valid to measure swallowing frequency and kinematics using electromyography and bioimpedance. The definitive study should have widened inclusion criteria and optimise intervention timing to maintain patient arousal.

Cyclosporin, methotrexate and prednisolone for graft-versus-host disease prophylaxis in allogeneic peripheral blood progenitor cell transplants.

The utility of GVHD prophylaxis with cyclosporin, MTX and prednisolone (CSA/MTX/Pred) in allogeneic PBPC transplants is not well described although there are published data using this combination after bone marrow transplants. The effectiveness of this regimen on the prevention of GVHD was assessed in 107 consecutive sibling and less-than-ideal donor transplant recipients over a 5-year period and compared to that observed in 65 patients receiving standard CSA and short-course MTX without prednisolone. Oral prednisolone was commenced on day +14 at 0.5 mg/kg per day, increased to 1 mg/kg per day on day +21 to day +34 then gradually tapered and ceased by day +100. The cumulative incidence of acute GVHD (grades II-IV) to day 100 in those receiving prednisolone prophylaxis was lower (52 versus 76%, P<0.01). The onset of symptomatic GVHD requiring systemic treatment was delayed from a median of 41 days post transplant to 92 days. When assessment of the cumulative incidence of symptomatic GVHD continued to day +180 incidence became similar (74 versus 78%), there was no difference between the two groups in rates of relapse, transplant-related mortality, infections or chronic GVHD. We conclude that the addition of prednisolone to CSA/MTX delays the onset of early acute GVHD in PBPC recipients but has no impact on the overall incidence of GVHD.

Adverse impact of high donor CD3+ cell dose on outcome following tandem auto-NMA allogeneic transplantation for high-risk myeloma.

High-risk (HR) multiple myeloma (MM) has poor outcomes with conventional therapy. Tandem autologous-non-myeloablative (NMA) allogeneic stem cell transplantation (autologous stem cell transplantation (ASCT)-NMA allogeneic SCT) is potentially curative secondary to graft-versus-myeloma effect. We retrospectively analysed ASCT-NMA allogeneic SCT outcomes of 59 HR and relapsed MM patients. At a median follow-up of 35.8 months, the outcomes for HR-MM upfront tandem ASCT-NMA allogeneic SCT and standard-risk (SR) MM upfront ASCT alone were comparable (median PFS 1166 days versus 1465 days, P=0.36; median overall survival (OS) not reached in both cohorts, P=0.31). The 5-year PFS and OS of patients who had ASCT-NMA allogeneic SCT after relapsing from previous ASCT were 30% and 48% respectively. High CD3+ cell dose (>3 × 108/kg) infusion was associated with more acute GvHD (grade 2-4) (47% vs 17.5%; P=0.03), extensive chronic GvHD (80% vs 50%; P=0.04), increased transplant-related mortality (26.3% vs 5%; P=0.009) and inferior OS (median OS 752 days vs not reached; P=0.002). On multivariate analysis, response achieved with tandem transplant (

PUMA promotes apoptosis of hematopoietic progenitors driving leukemic progression in a mouse model of myelodysplasia.

Myelodysplastic syndrome (MDS) is characterized by ineffective hematopoiesis with resultant cytopenias. Increased apoptosis and aberrantly functioning progenitors are thought to contribute to this phenotype. As is the case for other malignancies, overcoming apoptosis is believed to be important in progression toward acute myeloid leukemia (AML). Using the NUP98-HOXD13 (NHD13) transgenic mouse model of MDS, we previously reported that overexpression of the anti-apoptotic protein BCL2, blocked apoptosis and improved cytopenias, paradoxically, delaying leukemic progression. To further understand this surprising result, we examined the role of p53 and its pro-apoptotic effectors, PUMA and NOXA in NHD13 mice. The absence of p53 or PUMA but not NOXA reduced apoptosis and expanded the numbers of MDS-repopulating cells. Despite a similar effect on apoptosis and cell numbers, the absence of p53 and PUMA had diametrically opposed effects on progression to AML: absence of p53 accelerated leukemic progression, while absence of PUMA significantly delayed progression. This may be explained in part by differences in cellular responses to DNA damage. The absence of p53 led to higher levels of γ-H2AX (indicative of persistent DNA lesions) while PUMA-deficient NHD13 progenitors resolved DNA lesions in a manner comparable to wild-type cells. These results suggest that targeting PUMA may improve the cytopenias of MDS without a detrimental effect on leukemic progression thus warranting further investigation.

Loss-of-function mutations of Dynamin 2 promote T-ALL by enhancing IL-7 signalling.

Mutations in the DYNAMIN2 (DNM2) gene are frequently detected in human acute T-cell lymphoblastic leukemia (T-ALL), although the mechanisms linking these mutations to disease pathogenesis remain unknown. Using an ENU-based forward genetic screen for mice with erythroid phenotypes, we identified a heterozygous mouse line carrying a mutation in the GTPase domain of Dnm2 (Dnm2V265G) that induced a microcytic anemia. In vitro assays using the V265G mutant demonstrated loss of GTPase activity and impaired endocytosis that was comparable to other DNM2 mutants identified in human T-ALL. To determine the effects of DNM2 mutations in T-ALL, we bred the Dnm2V265G mice with the Lmo2 transgenic mouse model of T-ALL. Heterozygous Dnm2 mutants lacking the Lmo2 transgene displayed normal T-cell development, and did not develop T-ALL. In contrast, compound heterozygotes displayed an accelerated onset of T-ALL compared with mice carrying the Lmo2 oncogene alone. The leukemias from these mice exhibited a more immature immunophenotype and an expansion in leukemic stem cell numbers. Mechanistically, the Dnm2 mutation impaired clathrin-mediated endocytosis of the interleukin (IL)-7 receptor resulting in increased receptor density on the surface of leukemic stem cells. These findings suggest that DNM2 mutations cooperate with T-cell oncogenes by enhancing IL-7 signalling.

The CD2-scl transgene alters the phenotype and frequency of T-lymphomas in N-ras transgenic or p53 deficient mice.

Abnormal expression of SCL (TAL-1/TCL5) occurs in the majority of paediatric cases of acute T-cell lymphoblastic leukemia (T-ALL). Unexpectedly however, transgenic mice carrying scl coupled to the human T-cell specific CD2 enhancer (CD2-scl) did not spontaneously develop T-cell lymphomas despite high levels of scl expression in their thymocytes. Analogous to other transgenic models of lymphomagenesis, it is likely that additional genetic abnormalities are required to cooperate with scl to trigger lymphomagenesis. Two possible candidates are the p53 and N-ras genes which are mutated in some cases of T-ALL, particularly in relapsed disease. Therefore, we examined lymphomagenesis in the progeny of CD2-scl mice crossed with N-ras transgenic mice or p53 deficient. Surprisingly, the frequency of lymphomas in the p53 nullizygous or N-ras transgenic mice was not enhanced by expression of the scl transgene. In fact, expression of scl in both genetic backgrounds paradoxically reduced the frequency of thymic lymphomas and, at least in the p53 nullizygous mice, shifted the pattern of organ involvement to the peripheral lymphoid organs. In contrast, CD2-scl transgene expression accelerated lymphomagenesis in p53 heterozygous mice. These data suggest that the collaborative effects of scl with N-ras or p53 vary according to the developmental stage of the T-cell.

NF-Y regulates LIF-induced transcription of the signaling adaptor SKAP55R in myeloid cells.

Previously, we have shown that interleukin-6 (IL-6) or leukemia inhibitory factor (LIF)-induced differentiation of the myeloid cell line M1 was associated with a rapid increase in the level of mRNA encoding the signaling adaptor protein, SKAP55R. Furthermore, enforced over-expression of SKAP55R in primary bone marrow cells inhibited colony growth. In this study, we have identified the cis-acting elements that control SKAP55R transcription in myeloid cells. The 980 bp genomic sequence upstream of the transcriptional start site was cloned into a GFP reporter vector for transient (293 cells) or stable (M1 cells) transfection assays. This region contained cis-acting elements necessary for transcriptional activity in unstimulated 293 cells (10-fold higher levels than the control vector) or unstimulated M1 cells (two-fold higher levels). Significant LIF-induced transcription was observed in M1 (3.4-fold induction, P < 0.001), but not 293 cells. Deletion reporter constructs defined a promoter region (-317/-137) essential for the transcriptional activity in M1 cells. This region contained a CCAAT element recently implicated in IL-6/LIF-induced transcriptional regulation of junB in M1 cells. Mutation of the CCAAT element (-250/-246) significantly reduced both basal and LIF-induced transcription (P < 0.01). Electrophoretic mobility shift assays demonstrated that NF-Y bound to the CCAAT element of both SKAP55R and junB. These results suggest NF-Y binding may be a common mechanism of IL-6/LIF-regulated transcription in myeloid cells.

Systematic esophageal evaluation of patients with noncardiac chest pain.

We prospectively studied 73 patients with angina-like chest pain severe enough to warrant admission to a coronary care unit over a five-month period. Thirty-four patients (47%) were found to have coronary artery disease as the cause of their symptoms, based on exercise testing, stress radionuclide imaging, or cardiac catheterization. The remaining 39 patients had normal cardiac findings and then underwent videoesophagography, radionuclide esophageal transit study, and esophageal manometry. Thirty-three of the 39 underwent acid perfusion testing (modified Bernstein's test). The findings at esophageal manometry were abnormal in 29 (74%) of 39. Manometric diagnoses were "nutcracker esophagus" in 17 (59%), nonspecific esophageal motility disorders in nine (31%), diffuse esophageal spasm in two (7%), and achalasia in one (3%). Bernstein's test reproduced symptoms in only 12%. The sensitivity of videoesophagography in detecting esophageal motility disorders was 66%, and that of radionuclide esophageal transit was 79%. The positive predictive values were 86% and 85%, respectively.

Leukemic cells from murine myeloid leukemia display an intrinsic ability for autonomous proliferation.

OBJECTIVE: Human acute myeloid leukemia (AML) cells can proliferate in vitro in the absence of added growth factors when cultured at high cell density. Autocrine growth factor production is a postulated mechanism of autonomous growth. We sought to examine this using murine AML cells. MATERIALS AND METHODS: We have utilized a Moloney murine leukemia virus (M-MuLV) model of AML to investigate the nature of autonomous in vitro growth of myeloid leukemic cells. RESULTS: Like human AML, M-MuLV-induced myeloid leukemic cells displayed autonomous growth in unstimulated high cell density cultures. However, replating of individual, primary, growth factor autonomous colonies of leukemic cells demonstrated the presence of clonogenic cells capable of autonomous growth when cultured at low cell density. In addition, there was heterogeneity in the progeny of these cells: both factor-dependent leukemic cells and cells autonomous of exogenous factor were observed. CONCLUSION: We propose that clonogenic cells capable of autonomous growth at low cell density represent leukemic progenitors while the majority of leukemic cells derived from these "autonomous" leukemic cells are factor-dependent.

Adaptor protein SKAP55R is associated with myeloid differentiation and growth arrest.

Activation of the SRC family of protein tyrosine kinases is an important component of intracellular signaling in hematopoiesis, but their critical substrates are less well understood. In this report, we describe the cloning and functional characterization of murine SKAP55R (mSKAP55R), an SRC family kinase substrate. Expression of mSKAP55R was examined by Northern blot. Phosphorylation of mSKAP55R was examined by transient transfection of COS cells. For overexpression studies, mSKAP55R was cloned into a bicistronic murine stem cell virus-based retrovirus. Transduced cells (FDC-P1 cell line and murine bone marrow) were FACS isolated by expression of the selectable marker green fluorescent protein.mSKAP55R showed 90% amino acid identity to the recently published human SKAP55R. mSKAP55R contained a central pleckstrin homology domain, a C-terminal SH3 domain, and a putative SRC kinase consensus substrate DEIY(260). mSKAP55R was expressed in all hematopoietic lineages, with relative mRNA levels greatest in cells of the myeloid and erythroid lineages. Induced myeloid differentiation of M1 and HL-60 cell lines was associated with an eight-fold increase in mSKAP55R mRNA. Transient expression of mSKAP55R in COS cells demonstrated that tyrosine 260 was the predominant site of phosphorylation by FYN kinase. Furthermore, this phosphotyrosine was essential for coimmunoprecipitation of FYN with mSKAP55R. Enforced expression of mSKAP55R inhibited in vitro growth of the myeloid FDC-P1 cell line and primary hematopoietic progenitors. In contrast, a tyrosine 260 mutant mSKAP55R had no effect on in vitro growth. These studies implicate mSKAP55R in the processes of myeloid differentiation and growth arrest.

Effects of unidirectional flow shear stresses on the formation, fractal microstructure and rigidity of incipient whole blood clots and fibrin gels.

Incipient clot formation in whole blood and fibrin gels was studied by the rheometric techniques of controlled stress parallel superposition (CSPS) and small amplitude oscillatory shear (SAOS). The effects of unidirectional shear stress on incipient clot microstructure, formation kinetics and elasticity are reported in terms of the fractal dimension (df) of the fibrin network, the gel network formation time (TGP) and the shear elastic modulus, respectively. The results of this first haemorheological application of CSPS reveal the marked sensitivity of incipient clot microstructure to physiologically relevant levels of shear stress, these being an order of magnitude lower than have previously been studied by SAOS. CSPS tests revealed that exposure of forming clots to increasing levels of shear stress produces a corresponding elevation in df, consistent with the formation of tighter, more compact clot microstructures under unidirectional flow. A corresponding increase in shear elasticity was recorded. The scaling relationship established between shear elasticity and df for fibrin clots and whole blood confirms the fibrin network as the dominant microstructural component of the incipient clot in terms of its response to imposed stress. Supplementary studies of fibrin clot formation by rheometry and microscopy revealed the substantial additional network mass required to increase df and provide evidence to support the hypothesis that microstructural changes in blood clotted under unidirectional shear may be attributed to flow enhanced thrombin generation and activation. CSPS also identified a threshold value of unidirectional shear stress above which no incipient clot formation could be detected. CSPS was shown to be a valuable haemorheological tool for the study of the effects of physiological and pathological levels of shear on clot properties.

Timing in the normal pharyngeal swallow. Prospective selection and evaluation of 16 normal asymptomatic patients.

A review of timing of pharyngeal events with radiography has been made. A prospective selection of normal asymptomatic patients presenting for a gastrointestinal evaluation was made and timing of 55 events in the videorecorded pharyngeal swallow in these patients was performed. Only 16 normal asymptomatic patients as defined for selection were found among 870 patients presenting for gastroesophageal examination. A detailed description of their timing observations is presented. The timing data were used to temporally order events in the pharyngeal swallow. This ordering of events in the pharyngeal swallow and the data upon which it is based are reported here in detail.

Normal erect swallowing. Normal function and incidence of variations.

Of 871 candidates presenting for upper gastrointestinal examinations, 16 met the rigorous criteria established for selecting asymptomatic normal volunteers. Frame-by-frame evaluation of their videorecorded pharyngeal swallow confirmed many observations made previously utilizing cine recording at much higher radiation dosages. In addition, new observations were made: the nasopharynx may not occlude until the bolus is entirely within the pharynx; air mixes with the bolus if the swallow is an "open" type; the epiglottis always inverts in normal individuals regardless of the type of swallow ("open," air filled oro-and hypopharynx into which the swallowed bolus is dropped; "closed," airless oropharynx into which the swallowed bolus is pushed by a continuous peristaltic drive of the tongue and palate, thus reconstituting the pharyngeal space); laryngeal descent may aid in stripping the bolus from the pharynx; the vestibule may not completely close during the swallow and the larynx can still be impervious to the bolus; the peristaltic wave does not begin until the bolus has breeched the cricopharyngeus; the cricopharyngeus may be seen frequently in normal individuals, but does not delay the passage of the bolus; asymmetric flow of the bolus around the larynx is common and may not be the result of epiglottic tilt or head positioning.

Ranking: a year three follow-up in a different institution.

Ranking residents as a means of semiobjective evaluation of their overall performance was described in 1985. The predictive nature of pooled faculty ranking of residents was stressed. Ranking of resident total scores on The American College In-training Examination and American Board of Radiology written examination was noted to be statistically related to the pooled faculty ranking. Similarly, the faculty ranking was predictive of itself in subsequent rankings. A cohesiveness of faculty consensus was present such that small numbers (five minimum) were predictive of larger groups of participating faculty. All reported observations persist in the new institution. Exceptions to expected residency level of training stratification (eg, third-year residents ranking in the midst of first-year residents, second-year residents ranking above many third-year residents) continue to be the most useful observation in counseling residents. Additional information reported includes sensitivity of the ranking to improvement or nonimprovement of probated residents.

Testing as a teaching tool.

More than four years ago, the authors initiated testing as a means of obtaining data for evaluating residents. The testing process has evolved now and is used for its teaching value and as a means of objective resident self-evaluation. Testing is designed to provide 10 cases an hour, with characteristics allowing a single diagnosis as a unique answer. No history is provided because a common topic and anatomic area provide a context for each examination. Answers are given during the examination after each question, and discussion follows. All answers are written, and answer sheets are collected. Attendance is high. Test scores are routinely lower than in other forms of evaluation. Testing integrates all aspects of radiology training from cognitive through deductive, simulates written consultations, and provides a means of self-evaluation through rapid feedback. Testing is a viable form of teaching that blends self-evaluation with faculty and peer feedback.

Selecting radiology resident candidates.

Radiology resident candidate selection has become a burdensome, subjective, and somewhat arbitrary process. Because the luxury of many well-qualified candidates exists, there is an obligation to select them as honestly, equitably, and objectively as possible. Two years were spent in revising and modifying the resident selection process to make it more uniform and more efficacious. An application scoring form was devised to extract uniform pertinent information from the original application form. Candidates could then be ranked according to a numerical score derived from the form. This allowed easy selection of top candidates to be interviewed. A new interviewing scoring form was developed to include desirable characteristics of resident candidate performance. This form was also devised in such a way as to be easily scored and to allow selection of the top 20 to 25 candidates. These candidates were then ranked by participating faculty members while reviewing their application score forms and their interview forms. Positions for the residency training program were offered according to the ranking. The usefulness of both new forms was evaluated and confirmed by correlating form scores with faculty ranking of academic performance of current residents in the training program.

Evaluation of radiology resident cognitive performance.

Using radiographs and slides in three formats, we objectively tested the cognitive performance of 16 residents during an 8-month period. One format tested individual residents with radiographs and required only that a list of findings be provided within a week. For the second method, radiographs were projected to a small group of residents and a single diagnosis for each of ten cases was required. The third format required a larger group of competing residents to view projected slides of ten loosely defined but thematically connected cases and develop one diagnosis. Two of the test formats correlated significantly with a Spearmen rank, r = .50 or better (P less than .025) with a ranking based upon total score on the American College of Radiology Inservice Examination. All three test formats had a Spearmen rank r = .50 or better (P less than .05) when compared with pooled ranking performed by the staff radiologists.

Ranking: a reproducible semiobjective means of evaluating overall resident performance.

Eleven staff radiologists evaluated resident performance by independent subjective ranking regardless of residency year. A pooled ranking correlated with a ranking obtained from the total raw score of the American College of Radiology (ACR) Inservice Examination (P less than .005). The staff pooled ranking had a Spearman rank correlation, r = .70, with resident overall performance upon the ACR Inservice Examination. The pooled ranking had a Spearman rank correlation, r = .90, with a subsequent pooled ranking obtained six months later (P less than .0001). This method of ranking accurately predicts ACR Inservice Examination performance and appears to evaluate the objectivity of the staff radiologists involved.