Amplified EPOR/JAK2 Genes Define a Unique Subtype of Acute Erythroid Leukemia

Acute erythroid leukemia (AEL) is a unique subtype of acute myeloid leukemia characterized by prominent erythroid proliferation whose molecular basis is poorly understood. To elucidate the underlying mechanism of erythroid proliferation, we analyzed 121 AEL using whole-genome, whole-exome, and/or targeted-capture sequencing, together with transcriptome analysis of 21 AEL samples. Combining publicly available sequencing data, we found a high frequency of gains and amplifications involving EPOR/JAK2 in TP53-mutated cases, particularly those having >80% erythroblasts designated as pure erythroid leukemia (10/13). These cases were frequently accompanied by gains and amplifications of ERG/ETS2 and associated with a very poor prognosis, even compared with other TP53-mutated AEL. In addition to activation of the STAT5 pathway, a common feature across all AEL cases, these AEL cases exhibited enhanced cell proliferation and heme metabolism and often showed high sensitivity to ruxolitinib in vitro and in xenograft models, highlighting a potential role of JAK2 inhibition in therapeutics of AEL.

SIGNIFICANCE

This study reveals the major role of gains, amplifications, and mutations of EPOR and JAK2 in the pathogenesis of pure erythroleukemia. Their frequent response to ruxolitinib in patient-derived xenograft and cell culture models highlights a possible therapeutic role of JAK2 inhibition for erythroleukemia with EPOR/JAK2-involving lesions. This article is highlighted in the In This Issue feature, p. 369.

Influence of Killer Immunoglobulin-Like Receptors and Somatic Mutations on Transplant Outcomes in Acute Myeloid Leukemia

Natural killer (NK) cells are regulated by killer immunoglobulin-like receptor (KIR) interactions with human leukocyte antigen class I ligands. Various models of NK cell alloreactivity have been associated with outcomes after allogeneic hematopoietic cell transplant (alloHCT), but results have varied widely. We hypothesized that somatic mutations in acute myeloid leukemia (AML) in the context of KIR profiles may further refine their association with transplant outcomes. In this single-center, retrospective, observational study, 81 AML patients who underwent matched-related donor alloHCT were included. Post-HCT outcomes were assessed based on mutational status and KIR profiles with the Kaplan-Meier method and log-rank test. On multivariable analysis those with any somatic mutations and C1/C2 heterozygosity had less acute graft-versus-host disease (GvHD) (hazard ratio [HR], 0.32; 95% confidence interval [CI], 0.14-0.75; P = .009), more relapse (HR, 3.02; 95% CI, 1.30-7.01; P = .010), inferior relapse-free survival (RFS; (HR, 2.22; 95% CI, 1.17-4.20; P = .014), and overall survival (OS; HR, 2.21; 95% CI, 1.17-4.20; P = .015), whereas those with a missing KIR ligand had superior RFS (HR, 0.53; 95% CI, 0.30-0.94; P = .031). The presence of a somatic mutation and donor haplotype A was also associated with less acute GvHD (HR, 0.38; 95% CI, 0.16-0.92; P = .032), more relapse (HR, 2.72; 95% CI, 1.13-6.52; P = .025), inferior RFS (HR, 2.11; 95% CI, 1.07-4.14; P = .030), and OS (HR, 2.20; 95% CI, 1.11-4.38; P = .024). Enhanced NK cell alloreactivity from more KIR activating signals (donor B haplotype) and fewer inhibitory signals (recipient missing KIR ligand or C1 or C2 homozygosity) may help mitigate the adverse prognosis associated with some AML somatic mutations. These results may have implications for improving patient risk stratification prior to transplant and optimizing donor selection.

Clinical and basic implications of dynamic T cell receptor clonotyping in hematopoietic cell transplantation

TCR repertoire diversification constitutes a foundation for successful immune reconstitution after allogeneic hematopoietic cell transplantation (allo-HCT). Deep TCR Vβ sequencing of 135 serial specimens from a cohort of 35 allo-HCT recipients/donors was performed to dissect posttransplant TCR architecture and dynamics. Paired analysis of clonotypic repertoires showed a minimal overlap with donor expansions. Rarefied and hyperexpanded clonotypic patterns were hallmarks of T cell reconstitution and influenced clinical outcomes. Donor and pretransplant TCR diversity as well as divergence of class I human leukocyte antigen genotypes were major predictors of recipient TCR repertoire recovery. Complementary determining region 3–based specificity spectrum analysis indicated a predominant expansion of pathogen- and tumor-associated clonotypes in the late post–allo-HCT phase, while autoreactive clones were more expanded in the case of graft-versus-host disease occurrence. These findings shed light on post–allo-HCT adaptive immune reconstitution processes and possibly help in tracking alloreactive responses.

A Therapeutic Strategy for Preferential Targeting of TET2 Mutant and TET-dioxygenase Deficient Cells in Myeloid Neoplasms

TET2 is frequently mutated in myeloid neoplasms. Genetic TET2 deficiency leads to skewed myeloid differentiation and clonal expansion, but minimal residual TET activity is critical for survival of neoplastic progenitor and stem cells. Consistent with mutual exclusivity of TET2 and neomorphic IDH1/2 mutations, here we report that IDH1/2 mutant-derived 2-hydroxyglutarate is synthetically lethal to TET-dioxygenase deficient cells. In addition, a TET-selective small molecule inhibitor decreased cytosine hydroxymethylation and restricted clonal outgrowth of TET2 mutant, but not normal hematopoietic precursor cells in vitro and in vivo. While TET-inhibitor phenocopied somatic TET2 mutations, its pharmacologic effects on normal stem cells were, unlike mutations, reversible. Treatment with TET inhibitor suppressed the clonal evolution of TET2 mutant cells in murine models and TET2-mutated human leukemia xenografts. These results suggest that TET inhibitors may constitute a new class of targeted agents in TET2 mutant neoplasia.

Machine learning demonstrates that somatic mutations imprint invariant morphologic features in myelodysplastic syndromes

Morphologic interpretation is the standard in diagnosing myelodysplastic syndrome (MDS), but it has limitations, such as varying reliability in pathologic evaluation and lack of integration with genetic data. Somatic events shape morphologic features, but the complexity of morphologic and genetic changes makes clear associations challenging. This article interrogates novel clinical subtypes of MDS using a machine-learning technique devised to identify patterns of cooccurrence among morphologic features and genomic events. We sequenced 1079 MDS patients and analyzed bone marrow morphologic alterations and other clinical features. A total of 1929 somatic mutations were identified. Five distinct morphologic profiles with unique clinical characteristics were defined. Seventy-seven percent of higher-risk patients clustered in profile 1. All lower-risk (LR) patients clustered into the remaining 4 profiles: profile 2 was characterized by pancytopenia, profile 3 by monocytosis, profile 4 by elevated megakaryocytes, and profile 5 by erythroid dysplasia. These profiles could also separate patients with different prognoses. LR MDS patients were classified into 8 genetic signatures (eg, signature A had TET2 mutations, signature B had both TET2 and SRSF2 mutations, and signature G had SF3B1 mutations), demonstrating association with specific morphologic profiles. Six morphologic profiles/genetic signature associations were confirmed in a separate analysis of an independent cohort. Our study demonstrates that nonrandom or even pathognomonic relationships between morphology and genotype to define clinical features can be identified. This is the first comprehensive implementation of machine-learning algorithms to elucidate potential intrinsic interdependencies among genetic lesions, morphologies, and clinical prognostic in attributes of MDS.

Context dependent effects of ascorbic acid treatment in TET2 mutant myeloid neoplasia

Loss-of-function TET2 mutations (TET2^MT) are common in myeloid neoplasia. TET2, a DNA dioxygenase, requires 2-oxoglutarate and Fe(II) to oxidize 5-methylcytosine. TET2^MT thus result in hypermethylation and transcriptional repression. Ascorbic acid (AA) increases dioxygenase activity by facilitating Fe(III)/Fe(II) redox reaction and may alleviate some biological consequences of TET2^MT by restoring dioxygenase activity. Here, we report the utility of AA in the prevention of TET2^MT myeloid neoplasia (MN), clarify the mechanistic underpinning of the TET2-AA interactions, and demonstrate that the ability of AA to restore TET2 activity in cells depends on N- and C-terminal lysine acetylation and nature of TET2^MT. Consequently, pharmacologic modulation of acetyltransferases and histone deacetylases may regulate TET dioxygenase-dependent AA effects. Thus, our study highlights the contribution of factors that may enhance or attenuate AA effects on TET2 and provides a rationale for novel therapeutic approaches including combinations of AA with class I/II HDAC inhibitor or sirtuin activators in TET2^MT leukemia.

Using TET2- and ascorbic acid deficient model systems Guan et al show that long term treatment with ascorbic acid delays myeloid neoplasia in mice and reveal a complex interplay of post-translational modification of lysine residues that modulate TET2 activity in neoplastic evolution.

Complex landscape of alternative splicing in myeloid neoplasms

Myeloid neoplasms are characterized by frequent mutations in at least seven components of the spliceosome that have distinct roles in the process of pre-mRNA splicing. Hotspot mutations in SF3B1, SRSF2, U2AF1 and loss of function mutations in ZRSR2 have revealed widely different aberrant splicing signatures with little overlap. However, previous studies lacked the power necessary to identify commonly mis-spliced transcripts in heterogeneous patient cohorts. By performing RNA-Seq on bone marrow samples from 1,258 myeloid neoplasm patients and 63 healthy bone marrow donors, we identified transcripts frequently mis-spliced by mutated splicing factors (SF), rare SF mutations with common alternative splicing (AS) signatures, and SF-dependent neojunctions. We characterized 17,300 dysregulated AS events using a pipeline designed to predict the impact of mis-splicing on protein function. Meta-splicing analysis revealed a pattern of reduced levels of retained introns among disease samples that was exacerbated in patients with splicing factor mutations. These introns share characteristics with “detained introns,” a class of introns that have been shown to promote differentiation by detaining pro-proliferative transcripts in the nucleus. In this study, we have functionally characterized 17,300 targets of mis-splicing by the SF mutations, identifying a common pathway by which AS may promote maintenance of a proliferative state.

Molecular dissection of normal karyotype acute myeloid leukemia

7534

Background: Conventional cytogenetics remain one of the most important prognostic factors in acute myeloid leukemia (AML), though 50-60% of patients (pts) have normal karyotype (NK), conventionally classified as intermediate-risk, and have very heterogeneous outcomes. A fraction of mutations such as NPM1, FLT3-ITD, and CEBPa can improve risk stratification for some pts but underestimate the molecular complexity and interactions between these genes and others. Methods: Genomic and clinical data of 2,793 primary AML (pAML) pts were analyzed. A panel of 35 genes that are commonly mutated in AML and myeloid malignancies and have shown to impact OS was included. Correlation of each mutation with others and their impact on OS were evaluated. OS was calculated from the date of diagnosis to date of death or last follow-up. Results: Of 2,793 pts with pAML, 1,352 (48%) had NK and were included in the final analysis. The median age was 55 years (range, 18-93). The median number of mutations/sample was 3 (range, 0-7). The most commonly mutated genes were: NPM1 (49%), DNMT3A (37%), FLT3-ITD (24%), CEBPa (19%), TET2 (17%), IDH2 (17%), and RUNX1 (15%). In univariate Cox regression analysis, mutations in NPM1 (HR 0.81, p =0.008), and CEBPa (single mutant, HR 0.8, double mutant, HR 0.69, p< 0.001, respectively) were associated with longer OS, while mutations in DNMT3a (HR 1.26, p =0.003), FLT3-ITD (HR 1.49, p< 0.001), TET2 (HR 1.26, p =0.02), RUNX1 (HR 1.36, p =0.003), SRSF2 (HR 1.58, p <0.001), IDH1 (HR 1.29, p <0.001), and ASXL1 (HR 1.89, p <0.001) were associated with shorter OS. A total of 67% of pts had NPM1, DNMT3A, and FLT3-ITD mutated alone or in combination with each other. The median OS for pts with NMP1Mut/ DNMT3AWT/FLT3-ITDWT was 99.1 months(m), NMP1Mut/DNMT3AMut /FLT3-ITDWT 54.8m, NMP1Mu t/DNMT3AWT/FLT3-ITDMut 42.3m, NMP1Mut/DNMT3AMut/FLT3-ITDMut 13.4m, NMP1WT/DNMT3AMut/FLT3-ITDMut 13.1m, and NMP1WT/DNMT3AWT/FLT3-ITDWT (triple negative) 32.7m. The median OS for pts with 0-2 mutations/sample was 59.3m, compared to 34.1m for pts with 3-4 mutations, and 16.1m for pts with > 5 mutations ( p< 0.001). Conclusions: We propose a simplified and robust approach to risk stratify AML pts with NK based on the mutational status of NPM1, DNMT3A, FLT3-ITD (alone or in combination with each other), CEBPa, and the number of mutations/sample.

Invariant patterns of clonal succession determine specific clinical features of myelodysplastic syndromes

Myelodysplastic syndromes (MDS) arise in older adults through stepwise acquisitions of multiple somatic mutations. Here, analyzing 1809 MDS patients, we infer clonal architecture by using a stringent, the single-cell sequencing validated PyClone bioanalytic pipeline, and assess the position of the mutations within the clonal architecture. All 3,971 mutations are grouped based on their rank in the deduced clonal hierarchy (dominant and secondary). We evaluated how they affect the resultant morphology, progression, survival and response to therapies. Mutations of SF3B1, U2AF1, and TP53 are more likely to be dominant, those of ASXL1, CBL, and KRAS are secondary. Among distinct combinations of dominant/secondary mutations we identified 37 significant relationships, of which 12 affect clinical phenotypes, 5 cooperatively associate with poor prognosis. They also predict response to hypomethylating therapies. The clonal hierarchy has distinct ranking and the resultant invariant combinations of dominant/secondary mutations yield novel insights into the specific clinical phenotype of MDS.

Extended experience with a non-cytotoxic DNMT1-targeting regimen of decitabine to treat myeloid malignancies

The nucleoside analogue decitabine can deplete the epigenetic regulator DNA methyltransferase 1 (DNMT1), an effect that occurs, and is saturated at, low concentrations/doses. A reason to pursue this molecular-targeted effect instead of the DNA damage/cytotoxicity produced with high concentrations/doses, is that non-cytotoxic DNMT1-depletion can cytoreduce even p53-null myeloid malignancies while sparing normal haematopoiesis. We thus identified minimum doses of decitabine (0·1-0·2 mg/kg) that deplete DNMT1 without off-target anti-metabolite effects/cytotoxicity, and then administered these well-tolerated doses frequently 1-2X/week to increase S-phase dependent DNMT1-depletion, and used a Myeloid Malignancy Registry to evaluate long-term outcomes in 69 patients treated this way. Consistent with the scientific rationale, treatment was well-tolerated and durable responses were produced (~40%) in genetically heterogeneous disease and the very elderly.

Genomic Biomarkers to Predict Resistance to Hypomethylating Agents in Patients With Myelodysplastic Syndromes Using Artificial Intelligence

PURPOSE

We developed an unbiased framework to study the association of several mutations in predicting resistance to hypomethylating agents (HMAs) in patients with myelodysplastic syndromes (MDS), analogous to consumer and commercial recommender systems in which customers who bought products A and B are likely to buy C: patients who have a mutation in gene A and gene B are likely to respond or not respond to HMAs.

METHODS

We screened a cohort of 433 patients with MDS who received HMAs for the presence of common myeloid mutations in 29 genes that were obtained before the patients started therapy. The association between mutations and response was evaluated by the Apriori market basket analysis algorithm. Rules with the highest confidence (confidence that the association exists) and the highest lift (strength of the association) were chosen. We validated our biomarkers in samples from patients enrolled in the S1117 trial.

RESULTS

Among 433 patients, 193 (45%) received azacitidine, 176 (40%) received decitabine, and 64 (15%) received HMA alone or in combination. The median age was 70 years (range, 31 to 100 years), and 28% were female. The median number of mutations per sample was three (range, zero to nine), and 176 patients (41%) had three or more mutations per sample. Association rules identified several genomic combinations as being highly associated with no response. These molecular signatures were present in 30% of patients with three or more mutations/sample with an accuracy rate of 87% in the training cohort and 93% in the validation cohort.

CONCLUSION

Genomic biomarkers can identify, with high accuracy, approximately one third of patients with MDS who will not respond to HMAs. This study highlights the importance of machine learning technologies such as the recommender system algorithm in translating genomic data into useful clinical tools.

T-cell large granular lymphocytic leukemia evolution post-transplant: The Cleveland Clinic experience

e19072

Background: T-cell large granular lymphocytic leukemia (LGLL) has been reported after solid organ transplantation (SOT) and hematopoietic stem cell transplantation (HSCT); yet its underlying pathophysiological evolution has been poorly explained. Methods: We retrospectively screened a cohort of 243 LGLL patients at Cleveland Clinic for disease development post-transplantation and postulated several possible responsible pathophysiological mechanisms. Results: Five percent (n = 12) of the patients had a history of transplant. Of these, 67% (n = 8) had SOT (kidney, liver or heart) while 33% (n = 4) had HSCT. Twenty-five percent were females while 75% were males. The median age was 56 years (range: 15-65). The median time from transplant to diagnosis was 7 years. Conventional cytogenetic showed normal karyotype in 89% of the patients. TCR gene re-arrangement by PCR was detected in all tested individuals. Targeted deep sequencing identified somatic STAT3 mutations in 17% (n = 2) of the cases. Fifty percent (n = 6) had EBV DNA, IgM and/or IgG post-transplant. Forty-two percent (n = 5) had CMV DNA, IgM and/or IgG; of which 80% (n = 4) were post-transplant and 20% (n = 1) pre-transplant. The median survival from disease diagnosis was 64.3 months (8.37-232.9). Indeed, T-LGL clonal expansion resulted from long-term stimulation by viral antigens including EBV and CMV causing continuous cytotoxic T cell immune response or by “oncomodulation” as explained in 83% of patients. The latter theory suggests that CMV infects tumor cells and modulates their malignant properties, without direct transformation. Immunosuppression in setting of pre-transplant exposure to CMV, caused reactivation of the latent oncogenic viral genome as seen in 8% of patients. In 17% of cases that were seronegative for viral genome, graft allo-antigenic stimulation has triggered long-term recipient LGLL expansion from antigenic mismatch. Somatic STAT3 mutations, which are highly expressed in leukemic LGL, has led to aberrant signaling and transformation (17%). Conclusions: Our study highlights the complex nature of LGLL evolution post SOT and HSCT and points out confounding mechanisms. Certainly, investigating pre- vs. post-transplantation baseline, clinical and molecular characteristics is warranted to deeply understand this phenomenon.

Admissions for neutropenic fever in myelodysplastic syndromes (MDS)

e18548

Background: MDS are associated with a risk of severe infections due to disease course, patient (pt) age, co-morbidities and treatment. While infection rates have been reported for MDS patients enrolled in clinical trials, the real-world incidence of infections that require hospitalization, and how disease related factors (e.g. genetic mutations) affect the likelihood of infection remain unclear. Methods: Clinical data for MDS pts (per 2016 WHO criteria) diagnosed between 1/2010-12/2016, and treated at the Cleveland Clinic were included. TET2 mutation data obtained by NGS (in the context of genomic panel) was also included. Results: Our dataset included 214 pts of median age 70 years (range 13-99), with 33%, 54%, and 12% having low, intermediate, and high risk MDS according to IPSS-R. Overall, 100 admissions for neutropenic fever were recorded with a median length of stay of 5 days per admission; 63 (29%) pts required at least one admission, and of these 9 (14%) pts required 3 or more (up to 6) admissions. Blood cultures were positive in 17 (27%) pts with common organisms including Staphylococcus (38%), Enterococcus (35%), and Pseudomonas (12%). Urine cultures were positive in 6 (10%) pts, with organisms including E. Coli (50%), Pseudomonas (17%) and Klebsiella (17%). Fungal work up was sent in 18 (29%) pts and was positive in 3 (17%) pts. 13 (21%) pts required ICU transfer, and of those 7 (51%) pts required vasopressor support, and 10 (77%) pts required mechanical ventilation. Median ICU length of stay was 3 days (range 1-26). 13 (21%) pts were discharged on IV antibiotics. Median OS for the entire cohort was 18 months (95% CI 7.9 – 34.7), and median OS for admitted patients was not significantly shorter at 48 or 65 months. The number of admissions for neutropenic fever, length of stay, IPSS-R risk category, TET2 mutation, and ICU transfer did not impact survival. Conclusions: The risk of admission for neutropenic fever was 29% with blood cultures positive in 27% of pts. TET2 mutation status and IPSS-R risk did not impact admission rate, length of stay or ICU transfer.

Impact of germline CTC1 alterations on telomere length in acquired bone marrow failure

Compound heterozygous germline mutations in CTC1 gene have been found in patients with atypical dyskeratosis congenita (DC), whereas heterozygous carriers are unaffected. Through screening of a large cohort of adult patients with acquired bone marrow failure syndromes, in addition to a DC case, we have also found extremely rare or novel heterozygous deleterious germline variants of CTC1 in patients with aplastic anaemia (AA; n = 5), paroxysmal nocturnal haemoglobinuria (PNH; n = 3) and myelodysplastic syndrome (MDS; n = 2). A compound heterozygous case of AA showed clonal evolution. Our results suggest that some of the inherited CTC1 variants may represent predisposition factors for acquired bone marrow failure.

Kinematic differences between neutral and flat feet with and without symptoms as measured by the Oxford foot model

BACKGROUND

Flatfoot is a common presentation in children. It is usually asymptomatic, though a small number of children experience pain. Foot function during flatfoot walking is rarely considered, yet as an activity that places significant demands on the feet, this could explain the differences in terms of symptoms.

RESEARCH QUESTION

This paper investigates walking patterns in neutral and flat feet, with and without symptoms, to determine which kinematic parameters are associated with symptomatic flat feet.

METHODS

This is a retrospective study in which one hundred and six children between five and 18 years old were assessed by a physiotherapist for foot posture. Each foot was classified into one of four groups, giving 98 asymptomatic neutral, 47 asymptomatic mild flat, 29 asymptomatic flat, and 38 symptomatic flat feet with complete data for analysis. Using Plug-In-Gait and Oxford-Foot-Model markers, walking kinematics were measured, along with ground reaction forces. Median values of 14 lower limb joint angles were calculated at foot strike, midstance, and foot off. Each foot was treated as an independent sample. ANOVA and ANCOVA (with the speed-related variable relative stride length as the covariate) and post-hoc tests were used to assess whether angles differed between groups.

RESULTS

The symptomatic flat feet showed significant differences from asymptomatic groups (most commonly the neutral feet) in terms of hip flexion, knee flexion and varus, hindfoot inversion-eversion, and forefoot abduction-adduction. Increased forefoot abduction occurred throughout stance phase in symptomatic flatfooted participants compared to all asymptomatic groups.

SIGNIFICANCE

The results suggest that foot motion in the transverse plane is closely associated with the presence of symptoms in flat feet and that this is accompanied by changes in the kinematics of the ankle, knee, and hip.

Ultrasound-guided adductor canal block: a cadaver study investigating the effect of a thigh tourniquet

BACKGROUND

Placement of local anaesthetic within the adductor canal using ultrasonography is an alternative to femoral nerve blocks for postoperative pain relief after knee joint replacement surgery. However, the effect of an inflated thigh tourniquet on the distribution of local anaesthetic within the adductor canal is unknown. The aim of this cadaveric study was to compare the distribution of radio-opaque dye within the adductor canal in the presence or absence of an inflated thigh tourniquet.

METHODS

Bilateral ultrasound-guided adductor canal blocks were performed on the thawed lower limbs of five fresh frozen human cadavers. The left and right lower cadaver limbs were randomised to receive or not receive a thigh tourniquet inflated to 300 mm Hg for 1 h. X-rays with iohexol radio-opaque dye were obtained in four views, and fiducial markers inserted as reference points. Virtual editing technology was used to recreate outlines representing the distribution of the radio-opaque dye and superimpose these on anatomical images.

RESULTS

Radio-opaque dye was distributed on the medial aspect of the thighs with entire and well circumscribed margins. The majority of the radio-opaque dye was confined within the adductor canal. Superior-inferior dye distribution was 315 mm [95% confidence intervals (CI) 289-342] and 264 mm (95% CI 239-289) in the presence and absence of an inflated thigh tourniquet, respectively (diff 95% CI -80.46 to -22.22, P=0.0081). Image analysis using the recreated radio-opaque outlines suggested that the most proximal point of the radio-opaque dye was 100 mm (95% CI 82-117) or 117 mm (95% CI 62-171) below the inguinal ligament in the presence and absence of an inflated thigh tourniquet, respectively (diff 95% CI -38 to 72, P=0.456).

CONCLUSIONS

Application and inflation of thigh tourniquets significantly increased the combined superior-inferior dye distribution within the adductor canal of cadaveric limbs. There was insufficient evidence to suggest significant proximal spread of 25 ml of local anaesthetic to involve the motor branches of the femoral nerve. In some patients, the local anaesthetic may reach the popliteal fossa in close approximation to the sciatic nerve.

Static postural differences between neutral and flat feet in children with and without symptoms

BACKGROUND

Flatfoot is a common variant of foot posture. Whilst usually benign, in some children flatfoot is accompanied by pain and functional complaints. Comparisons between the posture of asymptomatic and symptomatic flat feet are few. If a difference does exist, it may help understand symptoms and guide management.

METHODS

This paper investigated differences in lower limb posture between neutral and flat feet with and without symptoms during standing using the multi-segment Oxford Foot Model. 97 children between five and 18years old were assessed by a physiotherapist; each foot was classified into one of four categories: asymptomatic neutral (n=88), asymptomatic mild flatfoot (n=47), asymptomatic flatfoot (n=29), or symptomatic flatfoot (n=30). For each child, Oxford Foot Model markers were applied, and mean values of 11-Euler angles at the foot, ankle, and knee joints during standing were calculated. Analysis of variance and post-hoc tests were used to identify differences between groups.

FINDINGS

Hindfoot eversion was significantly increased (P<0.001) in children with asymptomatic and, to a greater extent, symptomatic flatfoot. The forefoot was significantly more abducted (P<0.001) in the symptomatic than asymptomatic groups, and in the flat than neutral group. The forefoot was more supinated relative to the hindfoot in the flatfoot groups (P=0.023), although post-hoc analysis did not identify specific group differences.

INTERPRETATION

Hindfoot eversion and forefoot abduction were much greater in the symptomatic population. The differences in foot alignment may relate to the presence of symptoms.

Factors influencing the documentation of care

Nursing care plans should provide clear evidence of the quality of patient care provided. A study of a care plan used in a coronary care unit found that nurses were critical of the plan's format. Nurses need adequate education on the use of the chosen care plan and an understanding of the nursing model on which it is based.

Dosage of neostigmine for reversal of rocuronium block from two levels of spontaneous recovery

Spontaneous recovery, and recovery following neostigmine 20, 35 or 50 microgram.kg-1 administered at 10 or 25% of recovery of the first twitch of the train-of-four, was assessed in 80 patients after rocuronium administration under continued isoflurane anaesthesia. In an additional 40 patients, isoflurane administration was discontinued and neostigmine 35 or 50 microgram.kg-1 was given at 10 or 25% recovery. The administration of neostigmine reduced the recovery times significantly. A neostigmine dose of 20 microgram.kg-1 resulted in slower recovery compared with the higher doses, particularly when reversal was attempted at a first twitch height of 10%. Higher doses of neostigmine given at a first twitch height of 25% resulted in rapid reversal of block [mean (SD) times of 7.0 (4.8) and 6.4 (1.9) min with the 35 and 50 microgram.kg-1 doses, respectively, for attaining a train-of-four ratio of 0.8]. Discontinuing isoflurane did not alter recovery times. The incidence of emetic symptoms did not differ between groups, including one group that received atropine instead of glycopyrronium in combination with neostigmine. We conclude that rocuronium block can be antagonised safely using a neostigmine dose of 35 microgram.kg-1, although recovery may be slightly slower if administered at a first twitch of 10% of control.

Differential activation of p70 and p85 S6 kinase isoforms during cardiac hypertrophy in the adult mammal

An adult feline right ventricular pressure overload (RVPO) model was used to examine the two S6 kinase (S6K) isoforms, p70(S6K) and p85(S6K), that are involved in translational and transcriptional activation. Biochemical and confocal microscopy analyses at the level of the cardiocyte revealed that p70(S6K) is present predominantly in the cytosol, substantially activated in 1-h RVPO (>12 fold), and phosphorylated in the pseudosubstrate domain at the Ser-411, Thr-421, and Ser-424 sites. p85(S6K), which was localized exclusively in the nucleus, showed activation subsequent to p70(S6K), with a sustained increase in phosphorylation for up to 48 h of RVPO at equivalent sites of p70(S6K), Thr-421 and Ser-424, but not at Ser-411. Neither isoform translocated between the cytosol and the nucleus. Further studies to determine potential upstream elements of S6K activation revealed: (i) similar time course of activation for protein kinase C isoforms (alpha, gamma, and epsilon) and c-Raf, (ii) absence of accompanying phosphatidylinositol 3-kinase activation, (iii) activation of c-Src subsequent to p70(S6K), and (iv) similar changes in adult cardiocytes after treatment with 12-O-tetradecanoylphorbol-13-acetate. Thus, these studies suggest that a protein kinase C-mediated pathway couples pressure overload to growth induction via differential activation of S6K isoforms in cardiac hypertrophy.

Learning by reflection: the effect on educational outcomes

Learning by experience involves being able to reflect on a personal happening and through a process of analysis, come to understand it. Such an activity should result in 'deep learning' when carried out in a structured way. Higher education establishments are keen to develop such learning methods in students, as a secondary effect of this form of learning is to create student independence from the teacher. This is a much sought after ability as recent government changes have meant higher student numbers without a corresponding rise in teacher numbers. This threatens the quality of student knowledge unless it is compensated for in some way. This study sets out to examine the learning of two student groups. The experimental design was that of group comparison using matched pairs of students. One group, the experimental group, were exposed to reflective teaching methods, whilst the other group (the control group) were exposed to conventional teaching methods only. At the end of a set period of time, the learning achieved in both groups was estimated using an especially designed test paper. The results obtained from both groups were compared and it was found that there was no significant difference obtained in the learning between the groups (P>5%) Therefore, we concluded that students learnt just as well using reflective methods when compared to the conventional methods of learning. However, the potential for enhancement of learning was evident and invites further investigation. All the students in this study were on the Diploma in Higher Education (Nursing) course. The subject area used throughout the study was in the biological sciences.

Tuberculosis: disease of the past, disease of the present

Once thought to be under control, tuberculosis is now the number one cause of infection-related death worldwide and the sixth most significant cause of death overall. Transmission occurs by inhalation of airborne droplet nuclei that can be viable for days, and is facilitated by substance abuse, poverty, overcrowding, malnutrition, and, most importantly coinfection with human immunodeficiency virus. This article describes the history and current status of tuberculosis as a growing global health problem, transmission of the disease, risk factors for the general public and health care workers, and prevention of the disease.

Managing exposure to tuberculosis in the PACU: CDC guidelines and cost analysis

The Postanesthesia Care Unit (PACU) is an area of high risk for the transmission of Mycobacterium tuberculosis. The Centers for Disease Control (CDC) have recommended administrative controls, engineering controls, and personal protection devices to reduce the risks; nevertheless, perianesthesia nurses inhale airborne pathogens. The CDC guidelines are enforced by the Occupational Safety and Health Administration (OSHA). If an exposure occurs, the health-care facility has an OSHA-mandated course of action. The cost of follow-up of exposed persons can be high, depending on the patient census of the PACU at the time of unprotected exposure. This report presents the CDC guidelines for follow-up of exposure and costs based on typical surgical volumes and admission patterns for a large hospital with 10 thousand or more annual surgical procedures.

Concepts in nurse education

This paper reports a case study of student and senior nurses at the Royal Free Hospital, London, England. Qualitative methods were used to investigate the perceptions of nursing upon which students and senior nurses based their activities on the wards. Differences were identified between the ways in which students and senior nurses 'saw' their day-to-day tasks. Analysis showed that these differences were based upon differing levels of conceptualization. Student nurses were found to operate with low levels of conceptualization and were thus unable to categorize or group the patients, procedures or problems confronting them. Senior nurses, on the other hand, operated with a high level of conceptualization and were able to perceive similarities in objects, events and processes and to differentiate these into categories, classes or patterns. This allowed them to prioritize lines of action and to respond to situations in a rational and effective way. The problem for nurse education, then, is how best to enable students to develop a professional level of conceptualization. Strategies are identified by which senior nurses might enable student nurses to develop concepts in relation to their nursing activities on the wards.

Fungal peritonitis in patients on continuous ambulatory peritoneal dialysis

Fungal peritonitis is a rare complication in patients on continuous ambulatory peritoneal dialysis. We report five recent cases and their management. The fungi isolated were Candida albicans, C. parapsilosis, Exophiala jeanselmei, Drechslera spicifera, and a Fusarium species. Chemotherapy was attempted with various regimens including oral ketoconazole, intravenous or intraperitoneal amphotericin B, and oral flucytosine. Pharmacokinetic studies were done in two patients receiving treatment with one of these drugs. Three patients were cured of their fungal infection. Three patients whose Tenckhoff catheters were left in situ died, whereas two patients whose catheters were removed survived. Our experience suggests that removal of the peritoneal catheter should be considered once the diagnosis of fungal peritonitis is established.

Sodium concentration of homemade baby foods

Ingestion of excess salt may be an important factor in the development of hypertension in individuals who are predisposed to this disease genetically or through environmental factors. Some physicians and consumer groups have encouraged mothers to prepare their own baby foods, in part because of their concern that the physiologically unnecessary salt that is added by some commercial baby food manufacturers may lead to hypertension in adult life. This study presents data on the sodium concentration in 70 samples of homemade baby foods prepared by 36 mothers. The mean estimated amount of added salt was 0.41%/weight--64% higher than the maximum recommended by the Food and Nutrition Board of the National Academy of Sciences. Home-prepared foods had a sodium concentration 1,005% higher than similar baby food products made by Heinz and Beech-Nut and 24% higher than products made by Gerber. The data suggest that advice to parents to prepare their own baby food or to feed their infant food from the table should be tempered with the knowledge that these foods may contain higher salt concentrations than the commercial baby foods.