Retraction Note: Functional kinomics establishes a critical node of volume-sensitive cation-Cl- cotransporter regulation in the mammalian brain.
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Biomedical subjects
Publications and source records attributed to Paul Davies.
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BACKGROUND: The success of a Fontan circulation depends on several factors including low pulmonary vascular resistance. Pulmonary vascular resistance rises in response to hypoxia. Hypoxia is associated with altitude. Therefore, we wondered whether altitude is a risk factor for early failure after the Fontan operation. The aim was to test this hypothesis. METHODS: Data were obtained from all published series of 'total cavopulmonary' Fontan operations since 1990. The early failure rate from each series and the altitude of the respective cities were recorded. Early failure was defined as death, takedown of Fontan, or transplantation during the same hospital admission. The association between altitude and failure rate was investigated by rank correlation and logistic regression. RESULTS: 24 series were identified from centres situated at altitudes ranging from sea level to 520 metres. The plot of failure rate versus altitude suggests that failure rate increases with altitude. Logistic regression did not fit the data adequately. This was possibly due to the influence of unmeasured and unknown factors affecting the results, as well as the fact that centres were not randomly chosen but were self-selected by virtue of publishing their results. However, Spearman's rank correlation was 0.74 (p = 0.001). CONCLUSION: The early outcome of the Fontan circulation appears to be adversely affected by altitude.
Linear unselective CCR3 antagonist leads with IC(50) values in the 200 nM range were converted into low nM binding compounds selective at CCR3 by moving the piperidine nitrogen substituent to the carbon at the 2-position of the ring. Substitution of the piperidine nitrogen with simple alkyl and acyl groups was found to improve the selectivity of this new compound class. In particular, N-{3-[(2S, 4R)-1-(propyl)-4-(4-fluorobenzyl)piperidinyl]propyl}-N'-(3-acetylphenyl)urea exhibited single digit nanomolar IC(50) values for CCR3 with >100-fold selectivity against an extensive counter screen panel.
AIM: To describe the outcome of children with intestinal failure referred to Birmingham Children's Hospital (BCH) for consideration of intestinal transplantation (ITx), to determine factors for an adverse outcome and to analyse the impact of post-1998 strategies on survival. SUBJECTS AND METHODS: A retrospective analysis was performed of children referred for ITx assessment from January 1989 to December 2003. Children were assessed by a multidisciplinary team and categorised into: (a) stable on parenteral nutrition; (b) unsuitable for transplantation (Tx); and (c) recommended for Tx. To analyse the impact of the post-1998 strategies on survival, a comparison was made between the two eras (pre-1998 and post-1998). RESULTS: 152 children with chronic intestinal failure were identified (63M:89F, median age 10 months (range 1-170)). After assessment, 69 children were considered stable on parenteral nutrition (5-year survival 95%); 28 children were unsuitable for Tx (5-year survival 4%); and 55 children were recommended for Tx (5-year survival 35%, which includes 14 children who died waiting for size-matched organs). Twenty three ITx and nine isolated liver transplants (iLTx) were performed. In a multivariate analysis, the following factors in combination had an adverse effect on survival: the presence of a primary mucosal disorder (p = 0.007, OR ratio 3.16, 95% CI 1.37 to 7.31); absence of involvement of a nutritional care team at the referring hospital (p = 0.001, OR ratio 2.55, 95% CI 1.44 to 4.52); and a serum bilirubin>100 micromol/l (p = 0.001, OR ratio 3.70, 95% CI 1.84 to 7.47). Earlier referral (median serum bilirubin 78 micromol/l in the post-1998 era compared with 237 micromol/l in the pre-1998 era, p = 0.001) may be a contributory factor to improved survival. The strategies of combined en bloc reduced liver/small bowel transplantation and iLTx resulted in fewer deaths on the waiting list in the post-1998 era (2 deaths in post-1998 era v 12 deaths in pre-1998 era). The overall 3-year survival in the post-1998 era (69%) has improved compared with the pre-1998 era (31%; p<0.001) CONCLUSION: The changing characteristics at the time of referral, including earlier referral and innovative surgical strategies have resulted in improved long-term survival of children referred for ITx.
CC chemokine receptor (CCR) 3 is a chemokine receptor implicated in recruiting cells, particularly eosinophils (EPhi), to the lung in episodes of allergic asthma. To investigate the efficacy of selective, small molecule antagonists of CCR3, we developed a murine model of EPhi recruitment to the lung. Murine eotaxin was delivered intranasally to mice that had previously received i.p. injections of ovalbumin (OVA), and the effects were monitored by bronchoalveolar lavage. A selective eosinophilic influx was produced in animals receiving eotaxin but not saline. Furthermore, the number of EPhi was concentration- and time-dependent. Although anti-CCR3 antibody reduced the number of EPhi, the effect of eotaxin in OVA-sensitized mice was not a direct chemotactic stimulus because mast cell deficiency (in WBB6F1-Kitw/Kitw-v mice) significantly reduced the response. Two representative small molecule CCR3 antagonists from our program were characterized as being active at mouse CCR3. They were administered p.o. to wild-type mice and found to reduce eotaxin-elicited EPhi selectively in a dose-dependent manner. Pump infusion of one of the inhibitors to achieve steady-state levels showed that efficacy was not achieved at plasma concentrations equivalent to the in vitro chemotaxis IC90 but only at much higher concentrations. To extend the results from our recruitment model, we tested one of the inhibitors in an allergenic model of airway inflammation, generated by adoptive transfer of OVA-sensitive murine T helper 2 cells and aerosolized OVA challenge of recipient mice, and found that it inhibited EPhi recruitment. We conclude that small molecule CCR3 antagonists reduce pulmonary eosinophilic inflammation elicited by chemokine or allergenic challenge.
The long-term outcome of treatment with Interferon Alpha 2B with and without Prednisolone priming in children infected perinatally with hepatitis B was reviewed. The group studied included 48 children (aged 2-16 years), who were HBe antigen and hepatitis B DNA positive between 1991 and 1993. Twenty children were randomized to a therapeutic trial at that time, and received Prednisolone in reducing doses for 6 weeks and Interferon for 16 weeks while 22 children were monitored without treatment for 12 months. Fourteen of the untreated group and 6 additional children later received treatment with Interferon alone (n = 20). Eight children for whom treatment was declined were followed long term. Median follow-up was 7.5 years (range 1.5-10.6). There was no significant effect of Interferon therapy on seroconversion with or without Prednisolone at 12 months post-treatment compared to untreated children. On longer term follow-up, the 5-year HBeAg to anti-HBe seroconversion percentages, estimated from Kaplan-Meier curves, were 54% for Prednisolone plus Interferon, 22% for Interferon alone, and 12% for untreated children. The median time to seroconversion was 3.9 years (range 0.4-8.2) and was shortest in those treated with Prednisolone plus Interferon. Children who had elevated hepatic transaminase enzymes prior to treatment or during Prednisolone priming had a better response. In contrast to many European studies, no child cleared HBsAg and produced anti-HBs. Treatment with Prednisolone priming and Interferon, improved both the time and rate of seroconversion compared to no treatment or Interferon alone, suggesting that this combination of drugs might have an immunomodulatory effect.
STUDY DESIGN: A case of L4 spinous process avulsion following a hyperflexion injury treated with surgical excision. OBJECTIVE: To show that single photon emission computerized tomography is essential for the diagnosis and that excision can provide a successful outcome. SUMMARY OF BACKGROUND DATA: The avulsion resulted from a forced hyperflexion injury at the L4/5 area, where the interspinous ligament provides a high resistance to flexion. METHODS: A 29-year-old international rugby football player injured his low back during a match. Plain radiography and magnetic resonance imaging did not reveal the injury. Single photon emission computerized tomography and computerized tomography showed the lesion. RESULTS: Initial conservative therapy failed to control the symptoms, and, therefore, late excision was performed with pain-free return to contact sports at 3 months. CONCLUSIONS: Few cases of interspinous process avulsions have been described, and, to our knowledge, this is the first reported case of rugby football player who had a successful outcome with late surgical excision.
Starting with our previously described(20) class of CC chemokine receptor-3 (CCR3) antagonist, we improved the potency by replacing the phenyl linker of 1 with a cyclohexyl linker and by replacing the 4-benzylpiperidine with a 3-benzylpiperidine. The resulting compound, 32, is a potent and selective antagonist of CCR3. SAR studies showed that the 3-acetylphenyl urea of 32 could be replaced with heterocyclic ureas or heterocyclic-substituted phenyl ureas and still maintain the potency (inhibition of eotaxin-induced chemotaxis) of this class of compounds in the low-picomolar range (IC(50) = 10-60 pM), representing some of the most potent CCR3 antagonists reported to date. The potency of 32 for mouse CCR3 (chemotaxis IC(50) = 41 nM) and its oral bioavailability in mice (20% F ) were adequate to assess the efficacy in animal models of allergic airway inflammation. Oral administration of 32 reduced eosinophil recruitment into the lungs in a dose-dependent manner in these animal models. On the basis of its overall potency, selectivity, efficacy, and safety profile, the benzenesulfonate salt of 32, designated DPC168, entered phase I clinical trials.
The synthesis and structure-activity relationships of N-arylalkylpiperidylmethyl ureas as antagonists of the CC chemokine receptor-3 (CCR3) are presented. These compounds displayed potent binding to the receptor as well as functional antagonism of eotaxin-elicited effects on eosinophils.
STUDY DESIGN: A case of an odontoid nonunion in a child treated with anterior screw fixation. OBJECTIVES: To demonstrate that an anterior screw procedure can be performed with an odontoid nonunion with resultant fusion to maintain range of motion. METHODS: A 15-year-old boy presented with pain in his neck following a rugby football injury. Admission plain radiographs and computed tomography scan demonstrated an odontoid nonunion. Radiographs of a previous cervical spine injury 2 years before demonstrated a missed odontoid fracture. RESULTS: The child was initially treated conservatively with halo vest immobilization, which did not result in healing. Direct anterior screw fixation was performed and the fracture united 5 months following surgery. DISCUSSION: The nonunion was asymptomatic for 2 years until the second injury when it became clinically symptomatic. It did not respond to conservative treatment and was unstable on screening requiring operative intervention. CONCLUSIONS: Very few cases have been reported of pediatric odontoid nonunions. If the fracture pattern allows, then direct anterior screw fixation should be considered in order to maintain range of motion at the atlantoaxial articulation.
We describe a pilot study to investigate whether drawing "Thomas the Tank Engine" could be as effective a measure of developmental progress as the Goodenough-Harris Draw A Man test against the ThOMAs test (The Other Means of Assessment), with internal validation. The study included 95 children aged between 3 and 11 years of age, including a subgroup of 13 children with registered special needs from community and general pediatric clinics within Birmingham, UK, as a means of validation. There was no significant evidence that ThOMAS was either culturally or sex biased. Using regression analysis, nine items were found to correlate highly with actual age, and their total score gave a correlation of 0.563 with age. Adding further items did not increase this. After being converted into age-standardized scores, ThOMAS was as sensitive and specific as the Draw A Man test, and more so above a defined age-standardized threshold. This pilot study suggests that drawing Thomas the Tank Engine would appear to be as sensitive and specific a means of identifying children with special needs as the Goodenough-Harris Draw A Man test. The relatively small sample size means that further research is necessary to further define the age standardizations and to refine the ThOMAs test.
The discovery of novel and selective small molecule antagonists of the CC Chemokine Receptor-3 (CCR3) is presented. Simple conversion from a 4- to 3-benzylpiperidine gave improved selectivity for CCR3 over the serotonin 5HT(2A) receptor. Chiral resolution and exploration of mono- and disubstitution of the N-propylurea resulted in several 3-benzylpiperidine N-propylureas with CCR3 binding IC(50)s under 5 nM. Data from in vitro calcium mobilization and chemotaxis assays for these compounds ranged from high picomolar to low nanomolar EC(50)s and correlated well with antagonist binding IC(50)s.
BACKGROUND: Experimental data have suggested that early postoperative temperature management after cerebral ischemia may alter neurologic outcome. We explored whether minor deviations in early postoperative body temperature after infant heart surgery affects developmental outcome. METHODS: In a study of infants undergoing repair of congenital heart disease, 95% of whom had a period of deep hypothermic circulatory arrest, postoperative temperature data were collected following cardiac surgery. Subjects were infants who had been enrolled in one of two prospective randomized single-center trials. Development was tested at age one year (the Bayley Scales of Infant Development) and at four years (Wechsler Preschool and Primary Scale of Intelligence, including Full Scale IQ, a Verbal IQ, and a Performance IQ). RESULTS: Perioperative temperature data were reviewed in 329 patients, of whom 244 (74%) were evaluated at age one year and 156 (48%) were evaluated at four years. The temperature profile was recorded during the rewarming phase and for 36 hours postoperatively on the Intensive Care Unit. There were no significant associations between postoperative temperature and any of the neurodevelopmental tests at age one or four years. A further analysis assessing the percentage of time over specific temperature cutoff points of 37.5 degrees C, 38 degrees C, 38.5 degrees C, and 39 degrees C, revealed no significant effect. CONCLUSIONS: Neurodevelopmental outcome at one and four years after repair of complex congenital heart disease was not significantly affected by the early postoperative body temperature profile of the infant when a management strategy aiming for normothermia is employed.
Calcineurin inhibitor drugs (CNI), cyclosporin and tacrolimus are potent immunosuppressants, which have improved survival after liver transplantation. We evaluated long-term renal function in children receiving calcineurin inhibitors after liver transplantation. A retrospective analysis of all children undergoing orthotopic liver transplantation (OLT) from 1989 to 1999 who survived 1-yr post-transplantation was performed. All received prednisolone and either cyclosporin and azathioprine or tacrolimus. Steroids were withdrawn at 3 months and cyclosporin/tacrolimus monotherapy was initiated 12 months post-OLT. Calculated glomerular filtration rate (cGFR) was calculated using the modified Counahan-Barratt formula and measured pretransplant, 3, 6 and 12 months post-transplant and annually thereafter. Data were analysed in a serial manner to evaluate the trend of cGFR over time selectively using the Wilcoxon signed rank test and paired t-tests as appropriate. A total of 113 patients (65 males:48 females) were followed up for more than 1 yr (maximum 5 yr). Median (range) age at transplantation was 26 months (3-177). There was a significant fall of 35% in cGFR at 3 months compared with the pretransplant value (p = 0.001). By 12 months following the reduction in immunosuppression dosage, renal function stabilized with a slight improvement in cGFR which reached 76% of the pretransplant value at 5 yr (p < 0.001). Children who were <1 yr of age at the time of OLT had better recovery of renal function than older children (p = 0.02). No association was seen with sex, the type of immunosuppression or the underlying diagnosis. Renal dysfunction is a known complication of CNI therapy. Despite an initial reduction in cGFR, which was associated with maximal immunosuppression, long-term low dose CNI therapy was not associated with continued deterioration of renal function, particularly in children who were transplanted as infants.
Compensatory hypertrophy of a single functioning kidney is well described and has been shown to occur in utero. The long-term effects of hypertrophy and hyperfiltration in this situation are unknown. This study defined the growth parameters for single kidneys during childhood and correlated them with inulin clearance. Patients were those who had a radiologically "normal" single kidney, where the contralateral kidney was known to be non-functioning from infancy. Data were obtained from 74 children (40 boys and 34 girls) drawn from a registry of cases with a single kidney, and in whom simultaneous measurements of inulin clearance and renal length had been made at around 5, 10, and 16 years of age. Renal length was taken as the maximal bipolar measurement using real-time ultrasound scan. Inulin clearance was by continuous infusion technique. Nomograms for single kidney growth were determined against age, height, weight, and body surface area. Renal growth was correlated with inulin clearance. Renal length was found to correlate best with body surface area ( r=0.85, P<0.001), but this was not significantly superior to correlations with age, height, or weight separately. Inulin clearance per body surface area correlated positively with standardized renal length, i.e., Z score for renal length normalized for body surface area ( r=0.53, P<0.001). The larger kidneys have a higher glomerular filtration rate. Provided that the nephron number in the single kidney is similar to that in a paired kidney, single kidneys are hypertrophied and the single nephron glomerular filtration rate is likely to be abnormally high in these children.
We reviewed 45 children with cerebellar hypoplasia on magnetic resonance imaging to identify clinical features associated with cerebellar hypoplasia. We then studied children presenting with any likely associated clinical feature of cerebellar hypoplasia previously observed or reported. Two hundred fifty-one children, with one or more of these features, exhibited no cerebellar hypoplasia on imaging. We compared the children with cerebellar hypoplasia with those without cerebellar hypoplasia. Logistic regression and Pearson's chi(2) test were used. Of the 45 children with cerebellar hypoplasia, 39 exhibited developmental delay; 24, speech delay; 25, seizures; nine, microcephaly; 22, hypotonia; 22, ataxia and impaired coordination; four, abnormal movements (tremor or titubation); 13, hypertonia; eight, autistic features; and 18, ocular signs (nystagmus, strabismus, and abnormal ocular movements). Statistically significant clinical features of children with cerebellar hypoplasia compared with those without were development and speech delay, microcephaly, abnormal movements, ataxia and impaired coordination, autistic features, hypotonia, and ocular signs. The regression combination of speech delay, ataxia, hypotonia, autistic features, and ocular signs correctly predicted 86% of those with cerebellar hypoplasia. Main clinical features of cerebellar hypoplasia are developmental or speech delay, autistic features, ataxia, hypotonia, and ocular signs.
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