Potent and Selective Triazole-Based Inhibitors of the Hypoxia-Inducible Factor Prolyl-Hydroxylases with Activity in the Murine Brain

As part of the cellular adaptation to limiting oxygen availability in animals, the expression of a large set of genes is activated by the upregulation of the hypoxia-inducible transcription factors (HIFs). Therapeutic activation of the natural human hypoxic response can be achieved by the inhibition of the hypoxia sensors for the HIF system, i.e. the HIF prolyl-hydroxylases (PHDs). Here, we report studies on tricyclic triazole-containing compounds as potent and selective PHD inhibitors which compete with the 2-oxoglutarate co-substrate. One compound (IOX4) induces HIFα in cells and in wildtype mice with marked induction in the brain tissue, revealing that it is useful for studies aimed at validating the upregulation of HIF for treatment of cerebral diseases including stroke.

The treatment of stable paediatric forearm fractures using a cast that may be removed at home

We investigated whether, in the management of stable paediatric fractures of the forearm, flexible casts that can be removed at home are as clinically effective, cost-effective and acceptable to both patient and parent as management using a cast conventionally removed in hospital. A single-centre randomised controlled trial was performed on 317 children with a mean age of 9.3 years (2 to 16). No significant differences were seen in the change in Childhood Health Assessment Questionnaire index score (p = 0.10) or EuroQol 5-Dimensions domain scores between the two groups one week after removal of the cast or the absolute scores at six months. There was a significantly lower overall median treatment cost in the group whose casts were removed at home (£150.88 (sem 1.90) vs £251.62 (sem 2.68); p <  0.001). No difference was seen in satisfaction between the two groups (p = 0.48).

Cite this article: Bone Joint J 2013;95-B:1714–20.

Early chronic kidney disease in Aboriginal and non-Aboriginal Australian children: remoteness, socioeconomic disadvantage or race?

Indigenous people suffer substantially more end-stage kidney disease (ESKD), especially Australian Aboriginals. Previous work suggests causal pathways beginning early in life. No studies have shown the prevalence of early markers of chronic kidney disease (CKD) in both Indigenous and non-Indigenous children or the association with environmental health determinants--geographic remoteness and socioeconomic disadvantage. Height, weight, blood pressure, and urinary abnormalities were measured in age- and gender-matched Aboriginal and non-Aboriginal children from elementary schools across diverse areas of New South Wales, Australia. Hematuria was defined as>or=25 red blood cells/microl (>or=1+), proteinuria>or=0.30 g/l (>or=1+), and albuminuria (by albumin:creatinine)>or=3.4 mg/mmol. Remoteness and socioeconomic status were assigned using the Accessibility and Remoteness Index of Australia and Socio-Economic Indexes For Areas. From 2002 to 2004, 2266 children (55% Aboriginal, mean age 8.9 years) were enrolled from 37 elementary schools. Overall prevalence of hematuria was 5.5%, proteinuria 7.3%, and albuminuria 7.3%. Only baseline hematuria was more common in Aboriginal children (7.1 versus 3.6%; P=0.002). At 2-year follow-up, 1.2% of Aboriginal children had persistent hematuria that was no different from non-Aboriginal children (P=0.60). Socioeconomic disadvantage and geographical isolation were neither significant nor consistent risk factors for any marker of CKD. Aboriginal children have no increase in albuminuria, proteinuria, or persistent hematuria, which are more important markers for CKD. This suggests ESKD in Aboriginal people may be preventable during early adult life.

Interventions for idiopathic steroid-resistant nephrotic syndrome in children

BACKGROUND

The majority of children, who present with their first episode of nephrotic syndrome, achieve remission with corticosteroid therapy. Children who fail to respond to corticosteroids may be treated with immunosuppressive agents such as cyclophosphamide, chlorambucil or cyclosporin or with non-immunosuppressive agents such as ACE inhibitors. Optimal combinations of these agents with least toxicity remain to be determined. The aims of this systematic review are to assess the benefits and harms of interventions used to treat idiopathic steroid resistant nephrotic syndrome (SRNS) in children.

OBJECTIVES

We aimed to evaluate the benefits and harms of all interventions for children with SRNS.

SEARCH STRATEGY

Published and unpublished randomised controlled trials (RCTs) were identified from the Cochrane Controlled Trials Register, MEDLINE, EMBASE, reference lists of articles and abstracts from conference proceedings.

SELECTION CRITERIA

RCTs and quasi-RCTs were included if they compared different immunosuppressive agents or non-immunosuppressive agents with placebo, prednisone or other agent given orally or parenterally in children aged 3 months to 18 years with SRNS.

DATA COLLECTION AND ANALYSIS

Two reviewers independently searched the literature, determined trial eligibility, assessed quality, extracted data and entered it in RevMan. For dichotomous outcomes, results were expressed as relative risk (RR) and 95% confidence intervals (CI). Data were pooled using the random effects model.

MAIN RESULTS

Nine RCTs involving 225 children were included. Cyclosporin when compared with placebo or no treatment significantly increased the number of children who achieved complete remission (three trials, 49 children: RR for persistent nephrotic syndrome 0.64, 95% CI, 0.47 to 0.88). There was no significant difference in the number of children who achieved complete remission between oral cyclophosphamide with prednisone and prednisone alone (two trials, 91 children: RR 1.01, 95% CI 0.74 to 1.36), between intravenous cyclophosphamide and oral cyclophosphamide (one study, 11 children: RR 0.09, 95% CI 0.01 to 1.39) and between azathioprine with prednisone and prednisone alone (one trial 31 children: RR 1.01, 95% CI 0.77 to 1.32). No RCTs were identified comparing combination regimens comprising high dose steroids, alkylating agents or cyclosporin with single agents, placebo or no treatment.

REVIEWERS' CONCLUSIONS

Further adequately powered and well designed RCTs are needed to confirm the efficacy of cyclosporin and to evaluate other regimens for idiopathic SRNS including high dose steroids with alkylating agents or cyclosporin.

Parent-requested treatment

The decision about EPO was referred to and made by the Drug Committee, a committee of physicians, nurses and pharmacists. This committee has perforce to make decisions about drugs and vaccines, decisions which sometimes have a significant ethical component due to concerns about cost, safety and efficacy. Our hospital is considering developing a Clinical Ethics Advisory Committee, to assist with difficult ethical decisions such as this one. Should such a committee be asked to make acute ethical judgements on patient management? Larcher describes his ideal Hospital Ethics Committee as nonprescriptive, and suggests a more appropriate role is retrospective analysis and reflective discussion of clinical ethical problems. Such discussion may help with future rather than current management issues, and can help support clinicians in their decisions and hospital staff in their management of patients.

Non-corticosteroid treatment for nephrotic syndrome in children

BACKGROUND

Eighty to ninety per cent children with steroid sensitive nephrotic syndrome (SSNS) have one or more relapses. About half of these children relapse frequently and are at risk of the adverse effects of corticosteroids. Non-corticosteroid immunosuppressive agents are used to prolong periods of remission in children, who relapse frequently. However these non-corticosteroid agents also have significant potential adverse effects. Currently there is no consensus as to the most appropriate second line agent in children who are steroid sensitive, but who continue to relapse. In this systematic review of randomised controlled trials (RCTs), the benefits and harms of these immunosuppressive agents are evaluated.

OBJECTIVES

To evaluate the benefits and harms of non-corticosteroid immunosuppressive agents in relapsing SSNS in children.

SEARCH STRATEGY

Published and unpublished randomised controlled trials were identified from the Cochrane Controlled Trials Register, MEDLINE, EMBASE, reference lists of articles, abstracts from proceedings and contact with known investigators in the area.

SELECTION CRITERIA

Randomised or quasi-randomised trials were included if they were carried out in children (aged three months to 18 years) with relapsing SSNS, if they compared non-corticosteroid agents with placebo, prednisone or no treatment, different doses and/ or durations of the same non-corticosteroid agent, different non-corticosteroid agents and if they had outcome data at six months or more.

DATA COLLECTION AND ANALYSIS

Two reviewers independently reviewed all eligible studies for inclusion, assessed study quality and extracted data. The principle outcome measure was the number of children with and without relapse after six and 12 to 24 months. Secondary outcomes sought were the mean time to next relapse, the mean number of relapses per year and adverse events. A random effects model was used to estimate summary effect measures after testing for heterogeneity. Examination of possible between-study differences due to study quality, different interventions and different populations was attempted by subgroup analysis.

MAIN RESULTS

Eighteen trials involving 828 children were identified. Cyclophosphamide (three trials; relative risk (RR) 0.44; 95% confidence intervals (95% CI) 0.26 to 0.73) and chlorambucil (two trials; RR 0.13; 95% CI 0.03 to 0.57) significantly reduced the relapse risk at six to twelve months compared with prednisone alone. In the single chlorambucil versus cyclophosphamide trial, there was no observed difference in relapse risk at two years (RR 1.31; 95% CI 0.80 to 2.13). Cyclosporin was as effective as cyclophosphamide (one trial, RR 1.07; 95% CI 0.48 to 2.35) and chlorambucil (one trial, RR 0.82; 95% CI 0.44 to 1.53) but the effect was not sustained when cyclosporin was ceased. During treatment levamisole (three trials, RR 0.60; 95% CI 0.45 to 0.79) was more effective than steroids alone but the effect was not sustained. Mizoribine (one trial) and azathioprine (two trials) were no more effective than placebo or prednisone alone in maintaining remission.

REVIEWER'S CONCLUSIONS

Eight weeks courses of cyclophosphamide or chorambucil and prolonged courses of cyclosporin and levamisole reduce the risk of relapse in children with relapsing SSNS compared with corticosteroids alone. Clinically important differences in efficacy among these agents are possible and further comparative trials are still needed. Meanwhile choice between these agents depends on physician and patient preferences related to therapy duration and the type and frequency of complications.

The hindlimb in walking horses: 1. Kinematics and ground reaction forces

The objective was to study associations between kinematics and ground reaction forces in the hindlimb of walking horses. Video (60 Hz) and force (2000 Hz) data were gathered for 8 strides from each of 5 sound horses during the walk. Sagittal plane kinematics were measured concurrently with the vertical and longitudinal ground reaction forces. The hindlimb showed rapid loading and braking in the initial 10% stride. The stifle, tarsal and coffin joints flexed and the fetlock joint extended during this period of rapid loading. The vertical ground reaction force showed 2 peaks separated by a dip; this pattern was similar to the fetlock joint angle-time graph. Peaks in the longitudinal ground reaction force did not appear to correspond with kinematic events. Total braking impulse was equal to total propulsive impulse over the entire stride. Flexion and extension of the hip were responsible for protraction and retraction of the entire limb. Maximal protraction occurred shortly before the end of swing and maximal retraction occurred during breakover. During the middle part of stance the tarsal joint extended slowly, while the stifle began to flex when the limb was retracted beyond the midstance position at 28% stride. Flexion cycles of the stifle and tarsal joints were well coordinated during the swing phase to raise the distal limb as it was protracted. The results demonstrate a relationship between limb kinematics and vertical limb loading in the hindlimbs of sound horses. Future studies will elucidate the alterations in response to lameness.

The hindlimb in walking horses: 2. Net joint moments and joint powers

The objective of the study was to describe net joint moments and joint powers in the equine hindlimb during walking. The subjects were 5 sound horses. Kinematic and force data were collected synchronously and combined with morphometric information to determine net joint moments at each hindlimb joint throughout stance and swing. The results showed that the net joint moment was on the caudal/plantar side of all hindlimb joints at the start of stance when the limb was being actively retracted. It moved to the cranial/dorsal side around 24% stride at the hip and stifle and in terminal stance at the more distal joints. It remained on the cranial/dorsal side of all joints during the first half of swing to provide active limb protraction, then moved to the caudal/plantar aspect to reverse the direction of limb motion prior to ground contact. The hip joint was the main source of energy generation throughout the stride. It was assisted by the tarsal joint in both stance and swing phases and by the fetlock joint during the stance phase. The coffin joint acted as an energy damper during stance, whereas the stifle joint absorbed almost equal amounts of energy in the stance and swing phases. The coffin and fetlock joints absorbed energy as the limb was protracted and retracted during the swing phase, suggesting that their movements were driven by inertial forces. Future studies will apply these findings to detect changes in the energy profiles due to specific soft tissue injuries.

The forelimb in walking horses: 1. Kinematics and ground reaction forces

Video (60 Hz) and force (2000 Hz) data were collected from 5 sound horses during walking. Forelimb data were analysed for 8 strides (4 left, 4 right) per horse to determine sagittal plane kinematics and ground reaction forces (GRFs). The results suggested that brachial rotation was responsible for protraction and retraction of the limb as a whole, while rotations of the scapula and antebrachium elevated the distal limb during breakover and early swing then lowered it in preparation for ground contact. The coffin joint was flexed maximally at the time of peak longitudinal braking force, which occurred during breakover of the contralateral forelimb. The metacarpus was vertical at 28% stride. This was considerably earlier than the change from a braking to a propulsive longitudinal force (34% stride), which coincided with maximal extension of the fetlock joint. The longitudinal propulsive force peaked just after contact of the contralateral forelimb. During the swing phase the joints distal to the shoulder showed a single flexion cycle that peaked at 76% stride at the carpus, 81% stride at the fetlock and 84% stride at the elbow and coffin joints. The coffin and shoulder joints began to extend in the terminal swing phase and continued to extend through ground contact and early stance. The results provide normative data that will be applied in detecting changes in kinematics and ground reaction forces that are associated with specific lamenesses.

The forelimb in walking horses: 2. Net joint moments and joint powers

The objective was to measure the net joint moments and joint powers for the joints of the equine forelimb during the walk. Videographic and force data were combined with morphometric information using an inverse dynamics method. During stance phase the predominant joint moment was on the palmar aspect of all forelimb joints except the shoulder, where the peak moment was considerably higher than at any other joint. The entire forelimb showed net energy absorption in both stance and swing phases. The elbow was the only joint that showed net generation of energy, which was used to maintain the limb in extension in early stance as the horse's body vaults over the limb and to drive protraction and retraction of the limb during swing. The carpus aligned the limb into a supportive strut, but did not play an important role in energy absorption or generation. A small burst of positive work on the flexor aspect at the start of breakover indicated that the carpus played an active role in initiating breakover during walking. The fetlock functioned elastically to store and release strain energy during stance. The coffin joint acted as an energy damper during most of stance with a small burst of energy generation on the flexor aspect as the joint flexed during breakover. The magnitude of the peak joint power during swing decreased in a proximal to distal sequence. It is concluded that the elbow joint is the main site of energy generation. The shoulder and coffin joints act as energy dampers during stance. The distal joints had very low joint powers and appeared to be driven by inertial forces during the swing phase. This information will be applied to describe how horses compensate for different lamenesses in terms of redistributing the functions of energy generation and absorption between joints.

Increased surface expression of the membrane glycoprotein IIb/IIIa complex induced by platelet activation. Relationship to the binding of fibrinogen and platelet aggregation

Platelet activation altered the binding of three monoclonal antibodies (monovalent Fab' fragment) directed against the glycoprotein (GP) IIb/IIIa complex. An increased binding of two- to threefold occurred after stimulation with thrombin or phorbol myristate acetate (PMA), with slight but significant increase in the dissociation constants (Kd) of two antibodies (LJ-CP8 and LJ-P9). In contrast, no statistically significant changes were observed with ADP-stimulated platelets. The increased binding of LJ-CP3, but not of the other two antibodies, to activated platelets decreased by 30% to 40% in the presence of EDTA at 22 to 25 degrees C. Platelets stimulated by thrombin or PMA bound more fibrinogen than did those stimulated by ADP, and significant differences in the extent but not in the affinity of fibrinogen binding were observed with various platelet agonists. When the pool of GP IIb/IIIa molecules exposed on the surface of unstimulated platelets was reacted with the monoclonal antibody LJ-CP3 to block ADP-induced fibrinogen binding and platelet aggregation, stimulation with thrombin or PMA still induced substantial binding of antibody and fibrinogen, and aggregation ensued. Therefore, platelets exposed to "strong" agonists exhibit an increased number of surface-oriented epitopes associated with GP IIb/IIIa. The GP IIb/IIIa molecules bearing these newly exposed epitopes are functional in that they can bind fibrinogen and mediate platelet aggregation.

Independent modulation of von Willebrand factor and fibrinogen binding to the platelet membrane glycoprotein IIb/IIIa complex as demonstrated by monoclonal antibody

In this study we have used two new monoclonal antibodies, designated LJP5 and LJP9, as well as a previously described one, AP2, all specific for the platelet membrane glycoprotein (GP)IIb/IIIa complex. None of them reacted with dissociated GPIIb or GPIIIa. The monovalent Fab fragment of both LJP5 and LJP9 bound to unstimulated platelets in a saturable manner, but binding was markedly decreased after platelets had been incubated at 37 degrees C in the absence of added extracellular calcium. The binding of LJP9 was not affected by AP2, but was blocked by excess LJP5. On the contrary, the binding of LJP5 was blocked in the presence of both AP2 and LJP9. Thus, these antibodies bound to distinct epitopes of GPIIb/IIIa. At saturation, the binding to unstimulated platelets was between 2.41 and 10.9 X 10(4) molecules/platelet for LJP5 and between 3.47 and 9.1 X 10(4) molecules/platelet for LJP9 (range of 11 and 10 experiments, respectively). Binding increased up to 50% after thrombin stimulation. The estimated association constant, Ka, was 2.7 X 10(7) M-1 for LJP5 and 3.85 X 10(7) M-1 for LJP9. Both LJP5 and LJP9 partially inhibited the association of 45Ca2+ with the surface of unstimulated platelets. Moreover, both antibodies blocked the binding of von Willebrand factor (vWF) to stimulated platelets, whereas only LJP9, but not LJP5, blocked fibrinogen binding. LJP9 was also a potent inhibitor of platelet aggregation, whereas LJP5 was without effect in this regard. The results of the present study demonstrate that independent modulation of vWF and fibrinogen binding to stimulated platelets can be attained with monoclonal antibodies directed against distinct epitopes of GPIIb/IIIa.