The functional and psychological impact of delayed hip and knee arthroplasty: a systematic review and meta-analysis of 89,996 patients

This systematic review and meta-analysis aimed to determine the impact of presurgical waiting times on pre-/post-operative joint specific pain and function, health-related quality of life (HRQOL) and perspectives of patients awaiting primary elective total hip (THR) and knee (TKR) replacements. MEDLINE, EMBASE, PUBMED, and CENTRAL databases were searched from inception until 30th January 2023 (CRD42022288128). Secondary literature and unpublished datasets containing paediatric, non-elective, partial, or revision replacement populations were excluded. PRISMA 2020 reporting and GRADE certainty of evidence guidelines were followed. Residual maximum likelihood meta-analysis and linear meta-regression was performed to elucidate the influence of presurgical waiting time. Twenty-six studies were eligible for systematic review and sixteen for meta-analysis, capturing 89,996 patients (60.6% female, mean age 67.4 years) between 2001 and 2022. A significant deterioration in joint function (mean difference (MD):0.0575%; 95% CI 0.0064, 0.1086; p = 0.028(4d.p.); I2 = 73.1%) and HRQOL (MD: 0.05%; 95% CI - 0.0001.0009; p = 0.011(4 d.p.); I2 = 80.6%) was identified per additional day of waiting. Despite qualitative evidence, meta-analysis could not observe a relationship with postoperative outcome data. Patient responses to delayed THR and TKR surgery were unanimously negative. Immediate action should seek to reduce the increased patient anxiety and significant reductions in pre-operative joint functionality and HRQOL associated with prolonged pre-surgical waiting time, whilst mitigating any potential deleterious post-operative effects.

Systematic reanalysis of genomic data improves quality of variant interpretation

As genomic sequencing expands, so does our knowledge of the link between genetic variation and disease. Deeper catalogs of variant frequencies improve identification of benign variants, while sequencing affected individuals reveals disease-associated variation. Accumulation of human genetic data thus makes reanalysis a means to maximize the benefits of clinical sequencing. We implemented pipelines to systematically reassess sequencing data from 494 individuals with developmental disability. Reanalysis yielded pathogenic or likely pathogenic (P/LP) variants that were not initially reported in 23 individuals, 6 described here, comprising a 16% increase in P/LP yield. We also downgraded 3 LP and 6 variants of uncertain significance (VUS) due to updated population frequency data. The likelihood of identifying a new P/LP variant increased over time, as ~22% of individuals who did not receive a P/LP variant at their original analysis subsequently did after 3 years. We show here that reanalysis and data sharing increase the diagnostic yield and accuracy of clinical sequencing.

Role for Egr1 in the Transcriptional Program Associated with Neuronal Differentiation of PC12 Cells

PC12 cells are a well-established model to study how differences in signal transduction duration can elicit distinct cell behaviors. Epidermal growth factor (EGF) activates transient ERK signaling in PC12 cells that lasts 30–60 min, which in turn promotes proliferation; nerve growth factor (NGF) activates more sustained ERK signaling that lasts 4–6 h, which in turns induces neuronal differentiation. Data presented here extend a previous study by Mullenbrock et al. (2011) that demonstrated that sustained ERK signaling in response to NGF induces preferential expression of a 69-member gene set compared to transient ERK signaling in response to EGF and that the transcription factors AP-1 and CREB play a major role in the preferential expression of several genes within the set. Here, we examined whether the Egr family of transcription factors also contributes to the preferential expression of the gene set in response to NGF. Our data demonstrate that NGF causes transient induction of all Egr family member transcripts, but a corresponding induction of protein was detected for only Egr1 and 2. Chromatin immunoprecipitation experiments provided clearest evidence that, after induction, Egr1 binds 12 of the 69 genes that are preferentially expressed during sustained ERK signaling. In addition, Egr1 expression and binding upstream of its target genes were both sustained in response to NGF versus EGF within the same timeframe that its targets are preferentially expressed. These data thus provide evidence that Egr1 contributes to the transcriptional program activated by sustained ERK signaling in response to NGF, specifically by contributing to the preferential expression of its target genes identified here.

Transforming Growth Factor-β3 Therapy Delays Postoperative Reossification and Improves Craniofacial Growth in Craniosynostotic Rabbits

Postoperative reossification is a common clinical correlate following surgery. It has been suggested that an underexpression of transforming growth factor-β3 (TGF-β3) may be related to craniosynostosis and postoperative reossification. Adding TGF-β3 may delay reossification and improve postoperative growth. The present study was designed to test this hypothesis. Thirty 10-day-old New Zealand white rabbits with hereditary coronal suture synostosis were divided into three groups: (1) suturectomy controls (n = 14), (2) suturectomy treated with bovine serum albumin (n = 8), and (3) suturectomy treated with TGF-β3 protein (n = 8). At 10 days of age, a 3-mm × 15-mm coronal suturectomy was performed, and serial three-dimensional (3D) computed tomography (CT) scans and cephalographs were taken at 10, 25, 42, and 84 days of age. Calvaria were harvested at 84 days of age for histomorphometric analysis. Mean differences were analyzed using a group by age analysis of variance. Analysis of the 3D CT scan data revealed that sites treated with TGF-β3 had significantly (P < .05) greater defect areas and significantly (P < .05) greater intracranial volumes through 84 days of age compared with controls. Histomorphometry showed that sites treated with TGF-β3 had patent suturectomy sites and significantly (P < .001) less new bone in the suturectomy site compared with controls. Serial radiograph data revealed significant (P < .05) differences in craniofacial growth from 25 to 84 days in TGF-β3-treated rabbits compared with controls. Data show that TGF-β3 administration delayed reossification and improved craniofacial growth in this rabbit model. These findings also suggest that this molecular-based therapy may have potential clinical use.

Guidelines for investigating causality of sequence variants in human disease

The discovery of rare genetic variants is accelerating, and clear guidelines for distinguishing disease-causing sequence variants from the many potentially functional variants present in any human genome are urgently needed. Without rigorous standards we risk an acceleration of false-positive reports of causality, which would impede the translation of genomic research findings into the clinical diagnostic setting and hinder biological understanding of disease. Here we discuss the key challenges of assessing sequence variants in human disease, integrating both gene-level and variant-level support for causality. We propose guidelines for summarizing confidence in variant pathogenicity and highlight several areas that require further resource development.

Global expression analysis identified a preferentially nerve growth factor-induced transcriptional program regulated by sustained mitogen-activated protein kinase/extracellular signal-regulated kinase (ERK) and AP-1 protein activation during PC12 cell differentiation

Neuronal differentiation of PC12 cells in response to NGF is a prototypical model in which signal duration determines a biological response. Sustained ERK activity induced by NGF, as compared with transient activity induced by EGF, is critical to the differentiation of these cells. To characterize the transcriptional program activated preferentially by NGF, we compared global gene expression profiles between cells treated with NGF and EGF for 2-4 h, when sustained ERK signaling in response to NGF is most distinct from the transient signal elicited by EGF. This analysis identified 69 genes that were preferentially up-regulated in response to NGF. As expected, up-regulation of these genes was mediated by sustained ERK signaling. In addition, they were up-regulated in response to other neuritogenic treatments (pituitary adenylate cyclase-activating polypeptide and 12-O-tetradecanoylphorbol-13-acetate plus dbcAMP) and were enriched for genes related to neuronal differentiation/function. Computational analysis and chromatin immunoprecipitation identified binding of CREB and AP-1 family members (Fos, FosB, Fra1, JunB, JunD) upstream of >30 and 50%, respectively, of the preferentially NGF-induced genes. Expression of several AP-1 family members was induced by both EGF and NGF, but their induction was more robust and sustained in response to NGF. The binding of Fos family members to their target genes was similarly sustained in response to NGF and was reduced upon MEK inhibition, suggesting that AP-1 contributes significantly to the NGF transcriptional program. Interestingly, Fra1 as well as two other NGF-induced AP-1 targets (HB-EGF and miR-21) function in positive feedback loops that may contribute to sustained AP-1 activity.

A GSK-3-mediated transcriptional network maintains repression of immediate early genes in quiescent cells

Glycogen synthase kinase-3 (GSK-3) plays a central role in cell survival and proliferation, in part by the regulation of transcription. Unlike most protein kinases, GSK-3 is active in quiescent cells in the absence of growth factor signaling. In a recent series of studies, we employed a systems-level approach to understanding the transcription network regulated by GSK-3 in a quiescent cell model. We identified a group of immediate early genes that were upregulated in quiescent cells solely by the inhibition of GSK-3 in the absence of growth factor stimulation. Computational analysis of the upstream sequences of these genes identified statistically over-represented binding sites for the transcription factors CREB, NFκB and AP-1, and the roles of these factors in regulating expression of GSK-3 target genes were verified by chromatin immunoprecipitation and RNA interference. In quiescent cells, GSK-3 inhibits CREB, NFκB and AP-1, thereby maintaining repression of their target genes and contributing to maintenance of cell cycle arrest.

Saving mothers' lives: reviewing maternal deaths to make motherhood safer: 2006-8: a review

This review of the eighth report of the United Kingdom Enquiries into Maternal Deaths, Saving Mothers' Lives, is written primarily for anaesthetists and critical care specialists involved in both maternity and gynaecology services. Direct maternal deaths from systemic sepsis secondary to infection of the genital tract have increased. Systemic sepsis requires early recognition, immediate treatment and multidisciplinary management involving anaesthetists and critical care specialists. The incidence of deaths related to anaesthesia remains unchanged at seven in the three year period. Airway related problems unfortunately still cause maternal death. The role of early communication between obstetricians and anaesthesia and intensive care specialists is highlighted. The review summarizes the recommendations relating to anaesthesia and intensive care.

The E-box binding factors Max/Mnt, MITF, and USF1 act coordinately with FoxO to regulate expression of proapoptotic and cell cycle control genes by phosphatidylinositol 3-kinase/Akt/glycogen synthase kinase 3 signaling

Phosphatidylinositol (PI) 3-kinase/Akt signaling plays a critical role in cell proliferation and survival, partly by regulation of FoxO transcription factors. Previous work using global expression profiling indicated that inhibition of PI 3-kinase in proliferating cells led to induction of genes that promote cell cycle arrest and apoptosis. The upstream regulatory regions of these genes had binding sites not only for FoxO, but also for Myc/Max transcription factors. In the present study, we have addressed the role of Myc family members and related E-box-binding proteins in the regulation of these genes. Chromatin immunoprecipitations and RNA interference indicated that transcription was repressed by Max-Mnt-Sin3a-histone deacetylase complexes in proliferating cells. Inhibition of PI 3-kinase led to a loss of Max/Mnt binding and transcriptional induction by MITF and USF1, as well as FoxO. Both MITF and USF1 were activated by glycogen synthase kinase (GSK) 3, with GSK3 phosphorylation sites on USF1 identified as the previously described activating site threonine 153 as well as serine 186. siRNA against MITF as well as against FoxO3a protected cells from apoptosis following PI 3-kinase inhibition. These results define a novel E-box-regulated network that functions coordinately with FoxO to regulate transcription of apoptotic and cell cycle regulatory genes downstream of PI 3-kinase/Akt/GSK3 signaling.

The effects of testosterone on craniosynostotic calvarial cells: a test of the gene/environmental model of craniofacial anomalies

INTRODUCTION

The gene-environmental interaction model for craniofacial development proposes that if a genetic predisposition for an anomaly is coupled with an environmental factor that can exacerbate this predisposition, more severe phenotypes will result. Here, we utilize cells derived from our non-syndromic rabbit model of craniosynostosis to test the hypothesis that an insult, testosterone (TP) administration (exogenous source) will alter the osteogenic activity of these cells.

DESIGN

Calvarial cells from wild-type (WT) (N=13) or craniosynostotic (CS) rabbits (N=11) were stimulated with TP, an androgen receptor blocker, flutamide, and combined treatments. Proliferation and differentiation assays were conducted after 7 days. anova and t-tests were used to determine differences in stimulation and cell type.

RESULTS

The CS cells had significantly greater proliferation after TP administration compared to WT. There were no appreciable changes in differentiation after TP stimulation. Flutamide administration or combined TP and flutamide administration decreased both proliferation and differentiation for both cell types similarly.

CONCLUSIONS

Testosterone exposure caused an increase in cell proliferation for CS osteoblast cells. However, a therapy targeted to mitigate this response (flutamide therapy) similarly affected CS and WT cells, suggesting that the administration of flutamide or TP in the presence of flutamide decreases osteogenesis of these cells. Thus, although our data support a mechanism of gene-environmental interaction, these results would not support a therapeutic intervention based on this interaction.

AP-1 is a component of the transcriptional network regulated by GSK-3 in quiescent cells

BACKGROUND

The protein kinase GSK-3 is constitutively active in quiescent cells in the absence of growth factor signaling. Previously, we identified a set of genes that required GSK-3 to maintain their repression during quiescence. Computational analysis of the upstream sequences of these genes predicted transcription factor binding sites for CREB, NFκB and AP-1. In our previous work, contributions of CREB and NFκB were examined. In the current study, the AP-1 component of the signaling network in quiescent cells was explored.

METHODOLOGY/PRINCIPAL FINDINGS

Using chromatin immunoprecipitation analysis, two AP-1 family members, c-Jun and JunD, bound to predicted upstream regulatory sequences in 8 of the 12 GSK-3-regulated genes. c-Jun was phosphorylated on threonine 239 by GSK-3 in quiescent cells, consistent with previous studies demonstrating inhibition of c-Jun by GSK-3. Inhibition of GSK-3 attenuated this phosphorylation, resulting in the stabilization of c-Jun. The association of c-Jun with its target sequences was increased by growth factor stimulation as well as by direct GSK-3 inhibition. The physiological role for c-Jun was also confirmed by siRNA inhibition of gene induction.

CONCLUSIONS/SIGNIFICANCE

These results indicate that inhibition of c-Jun by GSK-3 contributes to the repression of growth factor-inducible genes in quiescent cells. Together, AP-1, CREB and NFκB form an integrated transcriptional network that is largely responsible for maintaining repression of target genes downstream of GSK-3 signaling.

Prolyl isomerase Pin1 regulates transcription factor LSF (TFCP2) by facilitating dephosphorylation at two serine-proline motifs

Transcription factor LSF is essential for cell cycle progression, being required for activating expression of the thymidylate synthase (Tyms) gene at the G1/S transition. We previously established that phosphorylation of LSF in early G1 at Ser-291 and Ser-309 inhibits its transcriptional activity and that dephosphorylation later in G1 is required for its reactivation. Here we reveal the role of prolyl cis-trans isomerase Pin1 in activating LSF, by facilitating dephosphorylation at both Ser-291 and Ser-309. We demonstrate that Pin1 binds LSF both in vitro and in vivo. Using coimmunoprecipitation assays, we identify three SP/TP motifs in LSF (at residues Ser-291, Ser-309, and Thr-329) that are required and sufficient for association with Pin1. Co-expression of Pin1 enhances LSF transactivation potential in reporter assays. The Pin1-dependent enhancement of LSF activity requires residue Thr-329 in LSF, requires both the WW and PPiase domains of Pin1, and correlates with hypophosphorylation of LSF at Ser-291 and Ser-309. These findings support a model in which the binding of Pin1 at the Thr-329-Pro-330 motif in LSF permits isomerization by Pin1 of the peptide bonds at the nearby phosphorylated SP motifs (Ser-291 and Ser-309) to the trans configuration, thereby facilitating their dephosphorylation.

Composite tissue vasculopathy and degeneration following multiple episodes of acute rejection in reconstructive transplantation

Transplant vasculopathy has not been systematically investigated in composite tissue allotransplantation (CTA). The impact of multiple acute rejections (ARs) on long-term graft outcomes in reconstructive transplantation remains unknown. This study in a rat hind-limb allotransplantation model systematically analyzes vasculopathy and tissue-specific pathological changes secondary to multiple AR episodes. LEW rats were transplanted with BN rat hind limbs and treated as follows: Group 1 (Iso): isografts. Group 2 (CsA): Cyclosporine (CsA) qd; Group 3 (mult AR): CsA and dexamethasone only when AR was observed. No AR was observed in Groups 1 and 2. Multiple AR were observed in Group 3, and each episode was completely reversed (clinically) with pulsed CsA + dexamethasone treatment. Group 3 animals demonstrated significant vascular lesions along with skin and muscle atrophy, upregulation of profibrotic gene expression and fibrosis when compared to Groups 1 and 2. In addition, allograft bone was sclerotic, weak and prone to malunion and nonunion. Interestingly, vasculopathy was a late finding, whereas muscle atrophy with macrophage infiltration was seen early, after only a few AR episodes. Taken together, multiple AR episodes lead to vasculopathy and tissue-specific pathology in CTA. This is the first evidence of 'composite tissue vasculopathy and degeneration (CTVD)' in CTA.

GSK-3 represses growth factor-inducible genes by inhibiting NF-kappaB in quiescent cells

GSK-3 is active in the absence of growth factor stimulation and generally acts to induce apoptosis or inhibit cell proliferation. We previously identified a subset of growth factor-inducible genes that can also be induced in quiescent T98G cells solely by inhibition of GSK-3 in the absence of growth factor stimulation. Computational predictions verified by chromatin immunoprecipitation assays identified NF-kappaB binding sites in the upstream regions of 75% of the genes regulated by GSK-3. p50 bound to most of these sites in quiescent cells, and for one-third of the genes, binding of p65 to the predicted sites increased upon inhibition of GSK-3. The functional role of p65 in gene induction following inhibition of GSK-3 was demonstrated by RNA interference experiments. Furthermore, inhibition of GSK-3 in quiescent cells resulted in activation of IkappaB kinase, leading to phosphorylation and degradation of IkappaB alpha and nuclear translocation of p65 and p50. Taken together, these results indicate that the high levels of GSK-3 activity in quiescent cells repress gene expression by negatively regulating NF-kappaB through inhibition of IkappaB kinase. This inhibition of NF-kappaB is consistent with the role of GSK-3 in the induction of apoptosis or cell cycle arrest in cells deprived of growth factors.

Recurrent reciprocal deletions and duplications of 16p13.11: the deletion is a risk factor for MR/MCA while the duplication may be a rare benign variant

BACKGROUND

Genomic disorders are often caused by non-allelic homologous recombination between segmental duplications. Chromosome 16 is especially rich in a chromosome-specific low copy repeat, termed LCR16.

METHODS AND RESULTS

A bacterial artificial chromosome (BAC) array comparative genome hybridisation (CGH) screen of 1027 patients with mental retardation and/or multiple congenital anomalies (MR/MCA) was performed. The BAC array CGH screen identified five patients with deletions and five with apparently reciprocal duplications of 16p13 covering 1.65 Mb, including 15 RefSeq genes. In addition, three atypical rearrangements overlapping or flanking this region were found. Fine mapping by high-resolution oligonucleotide arrays suggests that these deletions and duplications result from non-allelic homologous recombination (NAHR) between distinct LCR16 subunits with >99% sequence identity. Deletions and duplications were either de novo or inherited from unaffected parents. To determine whether these imbalances are associated with the MR/MCA phenotype or whether they might be benign variants, a population of 2014 normal controls was screened. The absence of deletions in the control population showed that 16p13.11 deletions are significantly associated with MR/MCA (p = 0.0048). Despite phenotypic variability, common features were identified: three patients with deletions presented with MR, microcephaly and epilepsy (two of these had also short stature), and two other deletion carriers ascertained prenatally presented with cleft lip and midline defects. In contrast to its previous association with autism, the duplication seems to be a common variant in the population (5/1682, 0.29%).

CONCLUSION

These findings indicate that deletions inherited from clinically normal parents are likely to be causal for the patients' phenotype whereas the role of duplications (de novo or inherited) in the phenotype remains uncertain. This difference in knowledge regarding the clinical relevance of the deletion and the duplication causes a paradigm shift in (cyto)genetic counselling.

Phosphatidylinositol 3-kinase signaling in proliferating cells maintains an anti-apoptotic transcriptional program mediated by inhibition of FOXO and non-canonical activation of NFkappaB transcription factors

BACKGROUND

Phosphatidylinositol (PI) 3-kinase is activated by a variety of growth factor receptors and the PI 3-kinase/Akt signaling pathway is a key regulator of cell proliferation and survival. The downstream targets of PI 3-kinase/Akt signaling include direct regulators of cell cycle progression and apoptosis as well as a number of transcription factors. Growth factor stimulation of quiescent cells leads to robust activation of PI 3-kinase, induction of immediate-early genes, and re-entry into the cell cycle. A lower level of PI 3-kinase signaling is also required for the proliferation and survival of cells maintained in the presence of growth factors, but the gene expression program controlled by PI 3-kinase signaling in proliferating cells has not been elucidated.

RESULTS

We used microarray analyses to characterize the changes in gene expression resulting from inhibition of PI 3-kinase in proliferating cells. The genes regulated by inhibition of PI 3-kinase in proliferating cells were distinct from genes induced by growth factor stimulation of quiescent cells and highly enriched in genes that regulate programmed cell death. Computational analyses followed by chromatin immunoprecipitations demonstrated FOXO binding to both previously known and novel sites in promoter regions of approximately one-third of the up-regulated genes, consistent with activation of FOXO1 and FOXO3a in response to inhibition of PI 3-kinase. NFkappaB binding sites were similarly identified in promoter regions of over one-third of the down-regulated genes. RelB was constitutively bound to promoter regions in cells maintained in serum, however binding decreased following PI 3-kinase inhibition, indicating that PI 3-kinase signaling activates NFkappaB via the non-canonical pathway in proliferating cells. Approximately 70% of the genes targeted by FOXO and NFkappaB regulate cell proliferation and apoptosis, including several regulators of apoptosis that were not previously known to be targeted by these transcription factors.

CONCLUSION

PI 3-kinase signaling in proliferating cells regulates a novel transcriptional program that is highly enriched in genes that regulate apoptosis. At least one-third of these genes are regulated either by FOXO transcription factors, which are activated following PI 3-kinase inhibition, or by RelB, which is activated by PI 3-kinase via the non-canonical pathway in proliferating cells.

Immediate-early and delayed primary response genes are distinct in function and genomic architecture

The transcriptional program induced by growth factor stimulation is classically described in two stages as follows: the rapid protein synthesis-independent induction of immediate-early genes, followed by the subsequent protein synthesis-dependent induction of secondary response genes. In this study, we obtained a comprehensive view of this transcriptional program. As expected, we identified both rapid and delayed gene inductions. Surprisingly, however, a large fraction of genes induced with delayed kinetics did not require protein synthesis and therefore represented delayed primary rather than secondary response genes. Of 133 genes induced within 4 h of growth factor stimulation, 49 (37%) were immediate-early genes, 58 (44%) were delayed primary response genes, and 26 (19%) were secondary response genes. Comparison of immediate-early and delayed primary response genes revealed functional and regulatory differences. Whereas many immediate-early genes encoded transcription factors, transcriptional regulators were not prevalent among the delayed primary response genes. The lag in induction of delayed primary response compared with immediate-early mRNAs was because of delays in both transcription initiation and subsequent stages of elongation and processing. Consistent with increased abundance of RNA polymerase II at their promoters, immediate-early genes were characterized by over-representation of transcription factor binding sites and high affinity TATA boxes. Immediate-early genes also had short primary transcripts with few exons, whereas delayed primary response genes more closely resembled other genes in the genome. These findings suggest that genomic features of immediate-early genes, in contrast to the delayed primary response genes, are selected for rapid induction, consistent with their regulatory functions.

Glycogen synthase kinase-3 represses cyclic AMP response element-binding protein (CREB)-targeted immediate early genes in quiescent cells

Despite its central role in cell survival and proliferation, the transcriptional program controlled by GSK-3 is poorly understood. We have employed a systems level approach to characterize gene regulation downstream of PI 3-kinase/Akt/GSK-3 signaling in response to growth factor stimulation of quiescent cells. Of 31 immediate-early genes whose induction was dependent on PI 3-kinase signaling, 12 were induced directly by inhibition of GSK-3. Most of the GSK-3-regulated genes encoded transcription factors, growth factors, and signaling molecules. Binding sites for CREB were highly over-represented in the upstream regions of these genes, with 9 genes containing CREB sites that were conserved in mouse orthologs. Binding sites predicted in 6 genes were confirmed by CREB chromatin immunoprecipitation and forskolin induction of CBP binding. Moreover, CREB siRNA substantially blocked induction of 5 genes by forskolin and of 3 genes following inhibition of GSK-3. These results indicate that GSK-3 actively represses gene expression in quiescent cells, with inhibition of CREB playing a key role in this transcriptional response.

Rapid turnover of mcl-1 couples translation to cell survival and apoptosis

Inhibition of translation plays a role in apoptosis induced by a variety of stimuli, but the mechanism by which it promotes apoptosis has not been established. We have investigated the hypothesis that selective degradation of anti-apoptotic regulatory protein(s) is responsible for apoptosis resulting from translation inhibition. Induction of apoptosis by cycloheximide was detected within 2-4 h and blocked by proteasome inhibitors, indicating that degradation of short-lived protein(s) was required. Caspase inhibition and overexpression of Bcl-x(L) blocked cycloheximide-induced apoptosis. In addition, cycloheximide induced rapid activation of Bak and Bax, which required proteasome activity. Mcl-1 was degraded by the proteasome with a half-life of approximately 30 min following inhibition of protein synthesis, preceding Bak/Bax activation and the onset of apoptosis. Overexpression of Mcl-1 blocked apoptosis induced by cycloheximide, whereas RNA interference knockdown of Mcl-1 induced apoptosis. Knockdown of Bim and Bak, downstream targets of Mcl-1, inhibited cycloheximide-induced apoptosis, as did knockdown of Bax. Apoptosis resulting from inhibition of translation thus involves the rapid degradation of Mcl-1, leading to activation of Bim, Bak, and Bax. Because of its rapid turnover, Mcl-1 may serve as a convergence point for signals that affect global translation, coupling translation to cell survival and the apoptotic machinery.

Haemodynamic effects of oxytocin given as i.v. bolus or infusion on women undergoing Caesarean section

BACKGROUND

The cardiovascular effects of oxytocin in animal models and women undergoing Caesarean section include tachycardia, hypotension and decrease in cardiac output. These can be sufficient to cause significant compromise in high-risk patients. We aimed to find a simple way to decrease these risks whilst retaining the benefits of oxytocin in decreasing bleeding after delivery. Method. We recruited 30 women undergoing elective Caesarean section. They were randomly allocated to receive 5 u of oxytocin either as a bolus injection (bolus group) or an infusion over 5 min (infusion group). These women had their heart rate and intra-arterial blood pressure recorded every 5 s throughout the procedure. The haemodynamic data, along with the estimated blood loss, were compared between the groups.

RESULTS

Marked cardiovascular changes occurred in the bolus group; the heart rate increased by 17 (10.7) beats min(-1) [mean (sd)] compared with 10 (9.7) beats min(-1) in the infusion group. The mean arterial pressure decreased by 27 (7.6) mm Hg in the bolus group compared with 8 (8.7) mm Hg in the infusion group. There were no differences in the estimated blood loss between the two groups.

CONCLUSION

We recommend that bolus doses should be used with caution, and further studies should ascertain if oxytocin is equally effective in reducing blood loss when given at a slower rate.

Obesity and obstetric anaesthesia

The prevalence of obesity continues to increase despite preventive strategies. Obese parturients are at increased risk of having either concurrent medical problems or superimposed antenatal diseases such as pre-eclampsia and gestational diabetes. Moreover, they have a tendency to labour abnormally contributing to increased instrumental delivery and Caesarean section. Obesity is a risk factor for anaesthesia related maternal mortality. Morbidly obese women must be considered as high-risk and deserve an anaesthetic consultation during their antenatal care. The significant difficulty in administering epidural analgesia should not preclude their use in labour. A more liberalised use of regional techniques may be a means to further reduce anaesthesia-related maternal mortality in the obese population. The mother's life should not be jeopardised to save a compromised fetus. Prophylactic placement of an epidural catheter when not contraindicated in labouring morbidly obese women would potentially decrease anaesthetic and perinatal complications associated with attempts at emergency provision of regional or general anaesthesia. Early mobilisation, aggressive chest physiotherapy and adequate pain control are essential components of effective postoperative care.

A randomized clinical trial of activated charcoal for the routine management of oral drug overdose

BACKGROUND

Activated charcoal (AC) is commonly used for the routine management of oral drug overdose.

AIM

To determine whether the routine use of activated charcoal has an effect on patient outcomes.

DESIGN

Randomized controlled unblinded trial.

METHODS

We recruited all adult patients presenting with an oral overdose at The Canberra Hospital, excluding only transfers, late presenters, those who had ingested drugs not adsorbed by activated charcoal or where administration was contraindicated, and very serious ingestions (at the discretion of the admitting physician). Patients were randomized to either activated charcoal or no decontamination.

RESULTS

The trial recruited 327 patients over 16 months. Of 411 presentations, four refused consent, 27 were protocol violations and 53 were excluded from the trial. Only seven were excluded due to the severity of their ingestion. The most common substances ingested were benzodiazepines, paracetamol and selective serotonin reuptake inhibitor antidepressants. More than 80% of patients presented within 4 h following ingestion. There were no differences between AC and no decontamination in terms of length of stay (AC 6.75 h, IQR 4-14 vs. controls 5.5 h, IQR 3-12; p=0.11) or secondary outcomes including vomiting, mortality and intensive care admission.

DISCUSSION

Routine administration of charcoal following oral overdose did not significantly influence length of stay or other patient outcomes following oral drug overdose. There were few adverse events. This does not exclude a role in patients who present shortly after ingestion of highly lethal drugs.

Maternal deaths from anaesthesia. An extract from Why Mothers Die 2000–2002 , the Confidential Enquiries into Maternal Deaths in the United Kingdom † †This article is accompanied by the Editorial

This is the first of two extracts from Why Mothers Die 2000-2002, issued on 12 November 2004 by the Confidential enquiry into Maternal and Child Health (CEMACH), reproduced with permission. The full report can be accessed via their web site: http://www.cemach.org.uk/

Two cases of severe postpartum anaemia in Jehovah's witnesses

Two cases of severe postpartum anaemia are presented in Jehovah's witnesses who refused blood transfusion. Despite haemoglobin concentrations of less than 3 g/dl both women survived. General management was directed to maximizing oxygen delivery and minimizing oxygen consumption. The use of an emulsified perfluorocarbon was organized for one of the cases, but was not administered because a snow storm prevented its delivery to the hospital. In the other case, recombinant human erythropoietin was used to encourage red cell production. The recovery of haemoglobin concentration in the two cases is compared.

A binding site for germ cell nuclear factor within c-mos regulatory sequences

The proto-oncogene c-mos is specifically expressed in male and female germ cells. Previous studies have shown that the orphan nuclear receptor chicken ovalbumin upstream promoter transcription factor (COUP-TF) contributes to the repression of c-mos in somatic cells by binding to an inverted hexamer repeat within the c-mos regulatory region. In the present study, we demonstrate that another nuclear receptor superfamily member, germ cell nuclear factor (GCNF), binds to a sequence overlapping the c-mos COUP-TF binding site. Electrophoretic mobility shift assays with recombinant GCNF and both wild-type and mutant c-mos oligonucleotides demonstrated the binding of GCNF to an extended half site, CCAAGTTCA, which overlaps the first hexamer of the COUP-TF binding site. Transient transfection assays in NIH 3T3 cells further demonstrated that GCNF fused to a VP16 activation domain stimulated transcription from reporter constructs containing the c-mos GCNF binding site. Since GCNF is expressed in male and female germ cells at the same stages of development at which c-mos is transcribed, these results suggest that GCNF may serve as a regulator of c-mos transcription. Mol. Reprod. Dev. 67: 55-64, 2004.

Identification of transcription factor binding sites upstream of human genes regulated by the phosphatidylinositol 3-kinase and MEK/ERK signaling pathways

We have taken an integrated approach in which expression profiling has been combined with the use of small molecule inhibitors and computational analysis of transcription factor binding sites to characterize regulatory sequences of genes that are targets of specific signaling pathways in growth factor-stimulated human cells. T98G cells were stimulated with platelet-derived growth factor (PDGF) and analyzed by DNA microarrays, which identified 74 immediate-early gene transcripts. Cells were then treated with inhibitors to identify subsets of genes that are targets of the phosphatidylinositol 3-kinase (PI3K) and MEK/ERK signaling pathways. Four groups of PDGF-induced genes were defined: independent of PI3K and MEK/ERK signaling, dependent on PI3K signaling, dependent on MEK/ERK signaling, and dependent on both pathways. The upstream regions of all genes in the four groups were scanned using TRANSFAC for putative cis-elements as compared with a background set of non-induced genes. Binding sites for 18 computationally predicted transcription factors were over-represented in the four groups of co-expressed genes compared with the background sequences (p < 0.01). Many of the cis-elements identified were conserved in orthologous mouse genes, and many of the predicted elements and their cognate transcription factors were consistent with previous experimental data. In addition, chromatin immunoprecipitation assays experimentally verified nine predicted SRF binding sites in T98G cells, including a previously unknown SRF site upstream of DUSP5. These results indicate that groups of human genes regulated by discrete intracellular signaling pathways share common cis-regulatory elements.

Mouse embryonic stem cells and preimplantation embryos require signaling through the phosphatidylinositol 3-kinase pathway to suppress apoptosis

Whereas most mammalian cells require extracellular signals to suppress apoptosis, preimplantation embryos can survive and develop to the blastocyst stage in defined medium without added serum or growth factors. Since cells of these embryos are capable of undergoing apoptosis, it has been suggested that their lack of dependence upon exogenous growth factors results from the production of endogenous growth factors that suppress apoptosis by an autocrine signaling mechanism. In the present study, we have examined the growth factor requirements and intracellular signaling pathways that suppress apoptosis in both mouse preimplantation embryos and embryonic stem (ES) cells, which are derived from the blastocyst inner cell mass. Cultured ES cells, in contrast to intact embryos, required serum growth factors to prevent apoptosis. Suppression of ES cell apoptosis by serum growth factors required the phosphatidylinositol 3-kinase (PI 3-kinase) signaling pathway, since apoptosis was rapidly induced by inhibition of PI 3-kinase with LY294002. In contrast, inhibition of MEK/ERK signaling with U0126 or of mTOR with rapamycin had no detectable effect on ES cell survival. Thus, like most mammalian cells, the survival of ES cells is mediated by growth factor stimulation of PI 3-kinase signaling. Treatment with LY294002 (but not with U0126 or rapamycin) similarly induced apoptosis of mouse blastocysts in serum-free medium, indicating that intact preimplantation embryos are also dependent upon PI 3-kinase signaling for survival. These results demonstrate that PI 3-kinase signaling is required to suppress apoptosis of both ES cells and intact preimplantation embryos, consistent with the hypothesis that survival of preimplantation embryos is maintained by endogenous growth factors that stimulate the PI 3-kinase pathway.

Mammalian transcription factor LSF is a target of ERK signaling

LSF is a mammalian transcription factor that is rapidly and quantitatively phosphorylated upon growth induction of resting, peripheral human T cells, as assayed by a reduction in its electrophoretic mobility. The DNA-binding activity of LSF in primary T cells is greatly increased after this phosphorylation event (Volker et al. [1997]: Genes Dev 11:1435-1446). We demonstrate here that LSF is also rapidly and quantitatively phosphorylated upon growth induction in NIH 3T3 cells, although its DNA-binding activity is not significantly altered. Three lines of experimentation established that ERK is responsible for phosphorylating LSF upon growth induction in both cell types. First, phosphorylation of LSF by ERK is sufficient to cause the reduced electrophoretic mobility of LSF. Second, the amount of ERK activity correlates with the extent of LSF phosphorylation in both primary human T cells and NIH 3T3 cells. Finally, specific inhibitors of the Ras/Raf/MEK/ERK pathway inhibit LSF modification in vivo. This phosphorylation by ERK is not sufficient for activation of LSF DNA-binding activity, as evidenced both in vitro and in mouse fibroblasts. Nonetheless, activation of ERK is a prerequisite for the substantial increase in LSF DNA-binding activity upon activation of resting T cells, indicating that ERK phosphorylation is necessary but not sufficient for activation of LSF in this cell type.

Maternal deaths from anaesthesia. An extract from Why mothers die 1997-1999, the Confidential Enquiries into Maternal Deaths in the United Kingdom

This article is reprinted from Why Mothers Die 1997-1999, the fifth report of the Confidential Enquiries into Maternal Deaths in the United Kingdom.

Functional analysis of sperm from c-mos(-/-) mice

The c-mos protooncogene, which is expressed predominantly in male and female germ cells, is crucial for normal oocyte meiosis and female fertility in mice. Inactivation of c-mos results in abnormal oocyte development and leads to ovarian cysts and tumors in vivo. In contrast to the severe effects of c-mos ablation in females, targeted inactivation of c-mos has not been reported to affect spermatogenesis in male mice. However, previously reported studies of male c-mos(-/-) mice have been limited to histological analyses of testes and in vivo matings, both of which are relatively insensitive indicators of sperm production and function. Therefore, we assayed sperm function of c-mos(-/-) males under in vitro conditions to determine whether the absence of Mos during development affected sperm production or fertilizing ability. We found no significant differences between the number of sperm collected from c-mos(-/-) and wild type mice. Additionally, sperm from c-mos(-/-) and c-mos(+/+) males performed equally well in assays of in vitro fertilization (IVF) and fertilization-associated events including zona pellucida (ZP) penetration, sperm/egg plasma membrane fusion, and sperm chromatin remodeling. Therefore, we suggest that the function of Mos in spermatogenesis is either not related to the ultimate fertilizing potential of the sperm, or else the absence of Mos is masked by a redundant kinase.

Role of mTOR in the degradation of IRS-1: regulation of PP2A activity

We have investigated the role of PI 3-kinase and mTOR in the degradation of IRS-1 induced by insulin. Inhibition of mTOR with rapamycin resulted in approximately 50% inhibition of the insulin-induced degradation of IRS-1. In contrast, inhibition of PI-3 kinase, an upstream activator of mTOR, leads to a complete block of the insulin-induced degradation. Inhibition of either PI-3 kinase or mTOR prevented the mobility shift in IRS-1 in response to insulin, a shift that is caused by Ser/Thr phosphorylation. These results indicate that insulin stimulates PI 3-kinase-mediated degradation of IRS-1 via both mTOR-dependent and -independent pathways. Platelet-derived growth factor (PDGF) stimulation leads to a lower level of degradation, but significant phosphorylation of IRS-1. Both the degradation and phosphorylation of IRS-1 in response to PDGF are completely inhibited by rapamycin, suggesting that PDGF stimulates IRS-1 degradation principally via the mTOR-dependent pathway. Inhibition of the serine/threonine phosphatase PP2A with okadaic acid also induced the phosphorylation and degradation of IRS-1. IRS-1 phosphorylation and degradation in response to okadaic acid were not inhibited by rapamycin, suggesting that the action of mTOR in the degradation of IRS-1 results from inhibition of PP2A. Consistent with this, treatment of cells with rapamycin stimulated PP2A activity. While the role of mTOR in the phosphorylation of IRS-1 appears to proceed primarily through the regulation of PP2A, we also provide evidence that the regulation of p70S6 kinase phosphorylation requires the direct activity of mTOR.

Cranial base changes following coronal suturectomy in craniosynostotic rabbits

It has been suggested that surgical release of synostosed sutures may ameliorate various cranial base abnormalities in craniosynostotic patients. The present study was designed to test this hypothesis in a rabbit model with familial coronal suture synostosis (CSS). Data were collected from 56 New Zealand White rabbits: 32 unaffected controls, 11 with unoperated CSS, and 13 with CSS released by suturectomy performed at 25 days of age. Serial radiographs were taken at 25, 42 and 84 days. Linear, angular and triangular shape cranial base measurements were compared using ANOVA and tensor biometric analysis. Results revealed that at 84 days, both groups of CSS rabbits had significantly (p < 0.05) different anterior and total cranial base lengths, flatter cranial base angles, and dysmorphic anterior cranial base shapes when compared with normals. Significant (p < 0.05) differences were noted only for palatal and cranial base angles and posterior cranial base shape between CSS rabbits with and without suturectomy. However, significant (p < 0.05) changes were noted between pre- and postoperative measurements in posterior and total cranial base lengths and anterior and posterior cranial base shapes in CSS rabbits with suturectomy. Results revealed that surgical release of synostosed coronal sutures through suturectomy did not normalize cranial base growth patterns in CSS rabbits. These findings may be explained by the relatively late age of surgical release or suturectomy site resynostosis with continued dysmorphic cranial base growth. Alternatively, cranial base abnormalities seen in CSS rabbits may be early primary malformations, not secondary deformations amenable to surgical modification.

Role of translation initiation factor 2B in control of cell survival by the phosphatidylinositol 3-kinase/Akt/glycogen synthase kinase 3beta signaling pathway

The phosphatidylinositol 3-kinase (PI 3-kinase)/Akt signaling pathway is an important mediator of growth factor-dependent survival of mammalian cells. A variety of targets of the Akt protein kinase have been implicated in cell survival, including the protein kinase glycogen synthase kinase 3beta (GSK-3beta). One of the targets of GSK-3beta is translation initiation factor 2B (eIF2B), linking global regulation of protein synthesis to PI 3-kinase/Akt signaling. Because of the central role of protein synthesis, we have investigated the involvement of eIF2B, which is inhibited as a result of GSK-3beta phosphorylation, in programmed cell death. We demonstrate that expression of eIF2B mutants lacking the GSK-3beta phosphorylation or priming sites is sufficient to protect both Rat-1 and PC12 cells from apoptosis induced by overexpression of GSK-3beta, inhibition of PI 3-kinase, or growth factor deprivation. Consistent with these effects on cell survival, expression of nonphosphorylatable eIF2B prevented inhibition of protein synthesis following treatment of cells with the PI 3-kinase inhibitor LY294002. Conversely, cycloheximide induced apoptosis of PC12 and Rat-1 cells, further indicating that protein synthesis was required for cell survival. Inhibition of translation resulting from treatment with cycloheximide led to the release of cytochrome c from mitochondria, similar to the effects of inhibition of PI 3-kinase. Expression of nonphosphorylatable eIF2B prevented cytochrome c release resulting from PI 3-kinase inhibition but did not affect cytochrome c release or apoptosis induced by cycloheximide. Regulation of translation resulting from phosphorylation of eIF2B by GSK-3beta thus appears to contribute to the control of cell survival by the PI 3-kinase/Akt signaling pathway, acting upstream of mitochondrial cytochrome c release.

Cranial base growth and morphology in second-trimester normal human fetuses and fetuses with cleft lip

OBJECTIVE

The present radiographic study describes the size and shape of the cranial base from the sagittal aspect for a sample of 77 second-trimester "normal" control fetuses (n = 61) and fetuses (n = 16) exhibiting isolated, unilateral clefts of the lip (CL), ranging in fertilization age from 10 to 22 weeks.

METHODS

Fetuses were placed in a cephalostat, and standardized, lateral head radiographs were taken. The radiographs were traced, and 15 cephalometric landmarks were identified and digitized for analysis. Growth curves for cranial base lengths, angles, and areas were compared between control and CL groups. Also, cranial base triangles were constructed and shape comparisons were made using tensor biometric analysis.

RESULTS

No significant differences (p >.05) in regression line slopes were noted for any comparisons between the control and CL samples. Tensor biometric analysis also revealed no significant differences in the shapes of various cranial base triangles between the control and CL samples.

CONCLUSION

This report presents second-trimester baseline growth curves for various cranial base components in CL human fetal specimens, and these data suggest that CL fetuses may also be used as an appropriate control sample for prenatal growth comparison studies of cleft lip and palate and cleft palate.

Correction of coronal suture synostosis using suture and dura mater allografts in rabbits with familial craniosynostosis

OBJECTIVE

Resynostosis following surgical correction of craniosynostosis is a common clinical correlate. Recent studies suggest that the dura mater is necessary to maintain suture patency. It has also been hypothesized that dura mater from synostotic individuals may provide aberrant biochemical signals to the osteogenic fronts of the calvaria, which result in premature suture fusion and subsequent resynostosis following surgery. This study was designed to test this hypothesis by surgically manipulating the coronal suture and dura mater in rabbits with familial craniosynostosis to prevent postsurgical resynostosis.

DESIGN

Craniofacial growth and histomorphometric data were collected from 129 rabbits: 72 normal controls and 57 rabbits with bilateral coronal suture synostosis (15 unoperated on controls; 13 surgical controls; 9 dura mater transplant only; 10 suture transplant only; and 10 suture and dura mater transplant). At 10 days of age, all rabbits had radiopaque amalgam markers placed on either side of the coronal, frontonasal, and anterior lambdoidal sutures. At 25 days of age, 42 synostosed rabbits had a 3 to 5-mm wide coronal suturectomy. Coronal sutures and/or underlying dura mater allografts were harvested from same-aged, wild-type, isohistogenic control rabbits and transplanted onto the dura mater of synostosed host rabbits. Serial radiographs were taken at 10, 25, 42, and 84 days of age, and the suturectomy sites were harvested at 84 days of age in 44 rabbits and serially sectioned for histomorphometric examination.

RESULTS

Results revealed that cranial vault growth was significantly (p < .05) improved following surgical release of the fused coronal suture compared with synostosed rabbits who were not operated on but was still significantly different (p < .05) from that of normal control rabbits. By 84 days of age, significant (p < .05) differences were noted in calvarial suture marker separation, cranial vault shape indices, and cranial base angles between rabbits with and without dura mater allografts, probably as a result of resynostosis of the suturectomy site or suture-only allografts. Qualitative histological examination revealed that at 84 days of age rabbits with suture and dura allografts had patent coronal sutures, suture-only allografts had fused coronal sutures with extensive endosteal hyperostosis, dura mater-only allografts had some new bone in the suturectomy site that resembled rudimentary osteogenic fronts, and suturectomy controls had extensive endosteal bone formation and resynostosis of the suturectomy site. Significantly (p < .05) more bone was found in the suturectomy sites of rabbits without dura mater allografts compared with rabbits with dura mater allografts.

CONCLUSIONS

Results support the initial hypothesis that normal dura mater allografts will maintain suture or suturectomy site patency and allow unrestricted craniofacial growth. However, it is still unclear whether the dura mater from normal rabbits was providing biochemical signals to the transplanted sutures or suturectomy sites or simply acting as a barrier to prevent abnormal biochemical signals from the dura mater of synostosed rabbits from reaching the calvaria. The clinical and therapeutic implications of these procedures are discussed.

Five cases of severe cardiac disease in pregnancy: outcomes and costs

The obstetric, medical and anaesthetic management of five pregnant patients with a variety of significant cardiac problems is briefly reviewed. The duration of hospitalisation, and the use of high dependency and intensive care are documented. Financial costs are estimated and their implications for the care of such patients during and following pregnancy are discussed.

Long-term morbidity following dural puncture in an obstetric population

Immediate and long-term symptoms, particularly headache, are recognised complications of dural puncture. To investigate long-term symptoms, a case-controlled retrospective questionnaire study was performed. The questionnaire was sent to 194 mothers who had suffered either accidental dural puncture during the placement of an epidural catheter or had developed a significant headache following spinal anaesthesia. The mothers were questioned about the nature and severity of symptoms and the impact upon their normal daily lives. They were also asked about the type and efficacy of any treatment they had received for these symptoms. An equal number of controls matched for ethnicity, age, modes of delivery and needle type were also questioned. There was increased reporting of new long-term headache and neckache in the spinal study group and an increased reporting of new long-term backache in the accidental dural puncture group compared to the epidural controls. These symptoms had a significant impact upon the mother's daily life and in some instances lasted for years. Disappointingly, although epidural blood patching was beneficial in the short term, it failed to produce any reduction in the incidence of long-term symptoms.

National obstetric anaesthetic practice in the UK 1997/1998

In the United Kingdom, the Royal College of Obstetricians and Gynaecologists requires maternity units recognised for training to complete annual statistical returns. Analysis of these data revealed that anaesthetists were directly involved in more than 251 000 procedures in the peripartum period in 1997/1998. There had been an increase in the number of women delivered by Caesarean section (18. 5% of all deliveries) compared with previous reports. The proportion of Caesarean sections performed under regional anaesthesia had increased for both elective and emergency Caesarean section deliveries (85.5% and 70.2%, respectively). For pain relief in labour, there had been neither an increase nor a decrease in the uptake of regional analgesia (23.6%). There were limited training opportunities for anaesthetists in general anaesthesia for Caesarean section and for obstetricians in vaginal breech delivery. The known admissions to intensive care units equated to over 100 women per month in the United Kingdom requiring intensive care as a result of childbirth.

Trigonocephaly in rabbits with familial interfrontal suture synostosis: the multiple effects of premature single-suture fusion

Previous studies from our laboratory have characterized the craniofacial morphology and growth patterns of an inbred strain of rabbits with autosomal dominant coronal suture synostosis. A number of rabbit perinates from this colony have been collected sporadically over a 5-year period with premature interfrontal suture synostosis. The present study describes the very early onset of craniofacial dysmorphology of these rabbits and compares them to similar-aged normal control rabbits. A total of 40 perinatal New Zealand White rabbits were used in the present study. Twenty-one comprised the sample with interfrontal suture synostosis and ranged in age from 27 to 38 days postconception (term = 31 days) with a mean age of 33.53 days (+/-2.84 days). Nineteen rabbits served as age-matched, normal controls (mean age = 33.05 days +/-2.79 days). Lateral and dorsoventral radiographs were collected from each rabbit. The radiographs were traced, computer digitized, and 12 craniofacial measurements, angles, and indices were obtained. Mean measures were compared using an unpaired Student's t-test. All synostosed rabbits were stillborn or died shortly after birth. Grossly, these rabbits exhibited extreme frontal bossing, trigonocephaly with sagittal keeling, and midfacial shortening. No somatic anomalies were noted. Radiographically, rabbits with interfrontal suture synostosis had significantly (P < 0.05) narrower bifrontal widths, shorter cranial vault lengths, kyphotic cranial base angles, and different cranial vault indices (shapes) compared to controls. Results reveal severe and early pathological and compensatory cranial vault changes associated with premature interfrontal suture synostosis in this rabbit model. The 100% mortality rate noted in this condition may be related to the inheritance of a lethal genetic mutation or to neural compression from reduced intracranial volume. Results are discussed in light of current pathogenic hypotheses for human infants with premature metopic suture synostosis.

Intra and inter technologist variability in the quality assessment of respiratory tract specimens

The majority of microbiology laboratories have implemented quality improvement procedures such as a Q scoring system to assess the nature of clinical specimens. Our study reviewed the sources and the amount of variation when Q scoring of lower respiratory secretions was performed. In total, 450 slides representing lower respiratory tract secretions were Q scored by three experienced technologists. Total agreement regarding the number of neutrophils, squamous epithelial cells and Q scores was 76%, 57% and 57% respectively. The major factor influencing Q score values was the enumeration of epithelial cells. From our findings, we expect that there is greater variability in Q scoring then is generally acknowledged and there is a substantial degree of subjectivity on part of individual technologists reading gram stains.