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Biomedical subjects

B M Jones

Publications and source records attributed to B M Jones.

At least 73 records · Page 4Linked to original sources
PubMed1996

Effect of 12 neutralizing anti-cytokine antibodies on in vitro activation of B-cells. Interleukin-12 is required by B1a but not B2 cells.

Normal human peripheral blood mononuclear cells, depleted of most monocytes and virtually all CD8-positive cells, were stimulated in vitro with pokeweed mitogen plus Staphylococcus aureus Cowan I in the presence or absence of various neutralizing anti-cytokine antibodies. Numbers of CD5+ and CD5- immunoglobulin-secreting cells were determined using the protein A haemolytic plaque assay after labelling B1a cells with anti-CD5-coated beads. Antibodies against IL-2, IL-5 and IL-10 had little or no effect on plaque-forming cell (PFC) induction; anti-IL-6, -TNF alpha and -TGF beta enhanced PFC induction; anti-IL-1 alpha, -IL-1 beta, -IL-4, -IFN gamma and -IL-13 suppressed PFC induction. B1a and B2 cells were equally affected by cytokine deprivation using these 11 neutralizing antibodies. In contrast, neutralizing anti-IL-12 suppressed induction of CD5+ but not CD5- PFC. Furthermore, recombinant IL-12, if added during the first 48 h of culture, enhanced CD5+ PFC induction while marginally suppressing (IgG-) or not affecting (IgA-, IgM-) induction of CD5- PFC. IL-12 did not preferentially increase survival in culture of B1a cells nor induce expression of CD5 on B2-cells. Further studies are required to determine whether manipulation of B1a and B2 subsets in vivo using IL-12 could be achieved in clinical situations where imbalances in the two populations have been observed.

B-Lymphocyte Subsets↗
PubMed1996

Cervical spine in Pfeiffer's syndrome.

Studies of cervical spine anomalies in patients with Crouzon's and Apert's syndromes have shown an increased incidence of fusions in comparison with that in the normal population. Currently, only small series of patients with Pfeiffer's syndrome who exhibit abnormalities have been published. The objective was to assess the incidence and pattern of radiological cervical spine abnormalities in patients with Pfeiffer's syndrome. All cervical spine radiographs of 22 patients with a confirmed diagnosis of Pfeiffer's syndrome treated at Great Ormond Street Hospital during the last 10 years were studied. All of the radiographs were reviewed by the craniofacial team along with a pediatric radiologist with experience in the assessment of skeletal dysplasias. Radiological abnormalities included hypoplasia of the neural arches, hemivertebrae, and a "butterfly" vertebra as well as vertebral fusion. Evidence of vertebral fusion was present in 16 (73%) of cases. Fusion of both the vertebral bodies and the posterior elements were noted. C2-C3 was the level most commonly involved, although fusion was noted at all levels within the cervical spine. Block fusions involving multiple vertebrae were noted. Analysis of sequential radiographs in 11 patients revealed evidence of progression in eight patients. These results reveal an incidence of anomalies that is higher than previously reported. The older age of the patients in our study demonstrates the progressive nature of the cervical fusions in Pfeiffer's syndrome.

Acrocephalosyndactylia↗
PubMed1996

The effectiveness of papilledema as an indicator of raised intracranial pressure in children with craniosynostosis.

Craniosynostosis management partially depends on the detection and treatment of elevated intracranial pressure (ICP). Examination for papilledema is considered to be the most reliable screening method for identifying raised ICP, but its effectiveness has not been defined. One hundred and twenty-two children with craniosynostosis who underwent funduscopic examinations and then Camino ICP monitoring were studied. All eye examinations were performed by an ophthalmologist after pharmacological pupillary dilation. Fifteen patients (12%) had papilledema. Subsequent ICP monitoring showed that the median ICP was 12.7 mm Hg, with 41 patients (34%) having elevated ICPs (> 15 mm Hg). Those with papilledema had higher ICPs (17.5 +/- 3.2 versus 12.7 +/- 5.5 mm Hg), were older (5.9 +/- 4.7 versus 1.9 +/- 2.6 years), and were more likely to have craniofacial syndromes (73 versus 41%) than those without papilledema (P < 0.05). Patients with both elevated ICPs and papilledema were older (5.9 +/- 4.7 versus 1.6 +/- 1.4 years) and more likely to have multiple-suture synostosis (92 versus 61%) than those with elevated ICPs and no papilledema (P < 0.05). The presence of papilledema was a specific (98%) indicator of raised ICP, but its sensitivity was age-dependent. It was 100% sensitive in children older than 8 years, but it indicated elevated ICP in only 22% of younger patients. These results suggest that ICP monitoring to document elevated ICP is unnecessary in children older than 8 years who have detailed ophthalmological examinations. In the younger child, the presence of papilledema reliably indicates elevated ICP but its absence does not rule out elevated ICP; formal ICP measurement has a greater role in detecting elevated ICP in these patients.

Adolescent↗
PubMed1996

The beaten copper cranium: a correlation between intracranial pressure, cranial radiographs, and computed tomographic scans in children with craniosynostosis.

OBJECTIVE: The beaten copper appearance of the cranium, as well as other cranial radiographic and computed tomographic findings in children with craniosynostosis, is often interpreted by clinicians as evidence of elevated intracranial pressure (ICP). However, a correlation between radiological findings and ICP measurements has not been previously demonstrated, and their usefulness in detecting elevated ICP has not been defined. METHODS: To address those issues, 123 children with craniosynostosis who had cranial radiographs and ICP monitoring were studied. To assess the specificity of certain radiological findings to patients with craniosynostosis, cranial radiographs of patients with craniosynostosis were compared to those of age- and sex-matched controls. In patients with craniosynostosis, findings on cranial radiographs were compared to computed tomographic scans of the brain. Radiographic findings were then correlated with ICP measurements obtained while the patient was sleeping, which was measured using a Camino fiberoptic ICP monitor (Camino Laboratories, San Diego, CA). All radiographs were independently analyzed by two radiologists who were blinded to clinical and ICP data. RESULTS: A diffuse beaten copper pattern, erosion of the dorsum sellar, and suture diastasis were seen more commonly in patients with craniosynostosis than in controls (P < 0.05), but the presence of the beaten copper pattern was no more common in children with craniosynostosis. ICP was greater when a diffuse beaten copper pattern, dorsum sellar erosion, suture diastasis, or narrowing of basal cisterns was present (P < 0.05). CONCLUSION: Although this study demonstrates that some cranial radiographic and computed tomographic findings do correlate with elevated ICP, the sensitivity of radiological methods for detecting elevated ICP is universally low and they are not recommended to screen for elevated ICP in children with craniosynostosis.

Child↗
PubMed1996

Is permanent congenital facial palsy caused by birth trauma?

OBJECTIVE: To study the relation between traumatic birth and the development of permanent facial palsy in the newborn. DESIGN: Retrospective case control study of children with 'congenital' facial palsy. SETTING: Two tertiary referral centres for patients with facial palsy. SUBJECTS: 61 children with established facial palsy. MAIN OUTCOME MEASURES: Odds ratios of recognised factors for birth injury: maternal primiparity, high birth weight, and the use of obstetric forceps at delivery. RESULTS: 13.2% of those studied had forceps assisted delivery compared to 10.2% in the normal population (odds ratio 1.34; 95% confidence intervals 0.61 to 2.97) 39.6% were born to primiparae compared to a national rate of 36.7% (1.13; 0.65 to 1.96) and only 18.9% weighed more than 3500 g at birth (0.37; 0.19 to 0.74). CONCLUSIONS: There is no association between the development of permanent 'congenital' facial palsy and recognised risk factors for birth injury. These data suggest an intrauterine rather than a traumatic aetiology.

Birth Injuries↗
PubMed1996

Congenital cervical spinal fusion: a study in Apert syndrome.

The occurrence and pattern of cervical spinal fusions have been assessed in 59 cases of Apert syndrome (acrocephalosyndactyly type 1). Radiological evidence of vertebral fusion either in progress or completed was observed in 37 (63%) of the cases. Fusion was limited to a single vertebral level in 18 cases and multiple levels, involving either contiguous or skipped levels in the remaining 19+ C3-4 and C5-6 were the levels most commonly involved. This distribution of fusions is different from other instances of congenital spinal fusion including those associated with other varieties of craniosynostosis. There was a significant association between age at the time of radiograph and the presence of spinal fusions (p < 0.001, Wilcoxon 2-sample test). Analysis of sequential radiographs in 17 patients revealed evidence of progressive fusion in 10. Small size of the vertebral body and reduced intervertebral disc space were indicators of subsequent bony fusion. The fusions seen in Apert syndrome thus appear to be progressive, occurring at the site of subtle congenital vertebral anomalies and may not be apparent as a congenital feature. The implications for the aetiology of so-called "congenital' spinal fusions in Apert syndrome and other situations are discussed.

Acrocephalosyndactylia↗
PubMed1996

Spectrum of craniosynostosis phenotypes associated with novel mutations at the fibroblast growth factor receptor 2 locus.

The causative relationship between several of the syndromic forms of craniosynostosis and mutations in the fibroblast growth factor receptor (FGFR) loci is now well established. However, within the group of patients with craniosynostosis, there are several families and sporadic cases whose clinical features differ in variable degrees from the classically described syndromes of craniosynostosis. In this communication we present novel FGFR2 mutations associated with a spectrum of craniosyostosis phenotypes in 4 sporadic cases and in one family in which craniosynostosis segregates. The mutation and phenotype data presented emphasise the clinical variability of mutations at this locus and underline the plasticity of the phenotype-genotype relationship in this important group of congenital malformation syndromes. Mutations found were tyrosine 105 to cysteine, glycine 338 to glutamic acid, serine 351 to cysteine and glycine 384 to arginine. These are the first reported mutations in the first immunoglobulin-like loop (tyrosine 105 to cysteine) and the transmembrane domain (glycine 384 to arginine) of FGFR2, providing further insights into the mechanism of abnormal receptor function in FGFR2 mutations.

Craniosynostoses↗
PubMed1996

Residence time and choice in concurrent foraging schedules.

Five pigeons were trained on a concurrent-schedule analogue of the "some patches are empty" procedure. Two concurrently available alternatives were arranged on a single response key and were signaled by red and green keylights. A subject could travel between these alternatives by responding on a second yellow "switching" key. Following a changeover to a patch, there was a probability (p) that a single reinforcer would be available on that alternative for a response after a time determined by the value of lambda, a probability of reinforcement per second. The overall scheduling of reinforcers on the two alternatives was arranged nonindependently, and the available alternative was switched after each reinforcer. In Part 1 of the experiment, the probabilities of reinforcement, rho(red) and rho(green), were equal on the two alternatives, and the arranged arrival rates of reinforcers, lambda(red) and lambda(green), were varied across conditions. In Part 2, the reinforcer arrival times were arranged to be equal, and the reinforcer probabilities were varied across conditions. In Part 3, both parameters were varied. The results replicated those seen in studies that have investigated time allocation in a single patch: Both response and time allocation to an alternative increased with decreasing values of lambda and with increasing values of rho, and residence times were consistently greater than those that would maximize obtained reinforcer rates. Furthermore, both response- and time-allocation ratios undermatched mean reinforcer-arrival time and reinforcer-frequency ratios.

Journal Article↗
PubMed1995

Fluoridation in Anglesey 1993: a clinical study of dental caries in 5-year-old children who had experienced sub-optimal fluoridation.

Several studies since the commencement of fluoridation in 1955 have demonstrated over 50% reduction in mean dmft for 5-year-old Anglesey children in comparison with local control groups. From 1987 fluoridation became intermittent and in 1991 it was terminated. In the present study, carried out in 1993, the total number of children examined was 725 (88.4% of the entire population of 5-year-old school children), of whom 498 had continually resided in specific water distribution zones. The mean dmft for the entire number examined was 2.01 (SD = 3.27). For those who had experienced fluoridation during approximately 35% of their lives (n = 230) it was 1.81 (SD = 2.86) and for those who had experienced fluoridation for less than 10% of their lives (n = 268) it was 2.28 (SD = 3.48). In 1987/88, the last year of optimal fluoridation, the mean dmft of Anglesey 5-year-old children was 0.80 (SD = 1.43) and for those resident on the non-fluoridated Gwynedd mainland it was 2.26 (SD = 3.17). The study demonstrates the serious consequences for dental health when fluoridation is withdrawn and how difficult it will be to reach dental health targets in North Wales without fluoridation.

Child, Preschool↗
PubMed1995

Facelifting: an initial eight year experience.

A retrospective analysis of facelifting experience during the author's initial 8 years of consultant practice is presented. 137 procedures are reviewed and the surgical technique described. 70% were SMAS-platysma lifts, 24% skin only lifts and 6% subperiosteal (mask) lifts. Particular attention was paid to complications, most common of which was haematoma requiring surgical evacuation in 3.6% of patients.

Adult↗
PubMed1995

Intracranial pressure in single-suture craniosynostosis.

The indications for surgical correction of craniosynostosis in which there is involvement of only one of the cranial vault sutures have traditionally been based upon the cosmetic merits of the deformity alone. Whilst it is now appreciated that intracranial hypertension is commonly associated with the more complex forms of craniosynostosis, this aspect has not previously been addressed in detail among cases of single-suture craniosynostosis. This retrospective study reports our experience of overnight subdural intracranial pressure monitoring in 74 children with premature closure of a single cranial suture. A single coronal suture was involved in 37 patients, the sagittal suture in 25 and the metopic suture in 12. Intracranial pressure was raised in 13 (17%), borderline in 28 (38%) and normal in 33 (45%). Elevated intracranial pressure was seen more commonly where a midline suture was involved (sagittal or metopic) than when a single coronal suture was fused. We conclude that intracranial hypertension occurs in a significant proportion of children with single-suture craniosynostosis and suggest that this factor should be borne in mind during the initial assessment of these children so as to enable timely intervention where required and appropriate counselling of parents.

Child↗
PubMed1995

A quantitative analysis of extreme choice.

Six homing pigeons were trained on a variety of concurrent variable-interval schedules in a switching-key procedure. Unlike previous work, reinforcer ratios of up to 160 to 1 and concurrent extinction variable-interval schedules were arranged in order to investigate choice when reinforcer-frequency outcomes were extremely different. The data obtained over 11 conditions were initially analyzed according to the generalized matching law, which fitted the data well. The generalized matching law was then fitted only to conditions in which the reinforcer ratios were between 1 to 10 and 10 to 1. The deviations of choice measures from the other four more extreme reinforcer-ratio conditions were significantly more towards equal choice than predicted by this second generalized matching fit. A contingency-discriminability model, which predicts such deviations, described the data more effectively than did the generalized matching law, and also correctly predicted the maintenance of responding on both alternatives when one was associated with extinction.

Journal Article↗
PubMed1995

Lessons from a case of kleeblattschädel. Case report.

The authors describe the clinical, radiological, and postmortem findings of a case of cloverleaf skull syndrome. The presence of hindbrain herniation, abnormal cervical segmentation, and atlantoaxial subluxation illustrate the anatomical complexity of the skull base and the craniocervical junction that may coexist in this condition. Unavoidable division of occipital emissary veins during elevation of the skin flap at the time of vault remodeling surgery led to an acute and, ultimately, fatal rise in intracranial pressure. Postmortem examination and review of magnetic resonance imaging revealed an anomalous pattern of venous drainage of the intracranial structures that appeared to have developed in response to venous obstruction, secondary to intraosseous venous sinuses and stenosis of the jugular foramina. The relationship between venous hypertension, hindbrain herniation, and hydrocephalus in this situation is reviewed, and the implications for evaluation and management of this vexing disorder are discussed.

Acrocephalosyndactylia↗
PubMed1994

Mutations in the fibroblast growth factor receptor 2 gene cause Crouzon syndrome.

Crouzon syndrome is an autosomal dominant condition causing premature fusion of the cranial sutures (craniosynostosis) and maps to chromosome 10q25-q26. We now present evidence that mutations in the fibroblast growth factor receptor 2 gene (FGFR2) cause Crouzon syndrome. We found SSCP variations in the B exon of FGFR2 in nine unrelated affected individuals as well as complete cosegregation between SSCP variation and disease in three unrelated multigenerational families. In four sporadic cases, the normal parents did not have SSCP variation. Finally, direct sequencing has revealed specific mutations in the B exon in all nine sporadic and familial cases, including replacement of a cysteine in an immunoglobulin-like domain in five patients.

Base Sequence↗
PubMed1994

An investigation of the differential-outcomes effect within sessions.

The differential-outcomes effect is manifest as more accurate performance of a delayed conditional discrimination when alternative choice responses are followed by different reinforcers than when they are followed by the same reinforcer. In Experiment 1, a differential-outcomes effect was demonstrated within sessions by signaling the duration of food access for correct responses with stimuli appearing in conjunction with the sample stimuli. The delayed matching-to-sample performance of 5 pigeons was more accurate when green choice responses (matching a green sample) were followed by 3.5-s food access and red choice responses (matching a red sample) were followed by 0.5-s food access (different-outcome trials) than when the correct choice responses were both followed by 1.5-s reinforcers (same-outcome trials). In Experiment 2, the acquisition of this differential-outcomes effect was characterized by a progressive decrease in rate of forgetting on different-outcome trials and no change in rate of forgetting on same-outcome trials. In addition, accuracy at the shortest delay intervals for both different-outcome and same-outcome trials increased over acquisition, but to a greater extent for different-outcome trials. These data suggest that both memorial and attentional (time-dependent and time-independent) factors contribute to the differential-outcomes effect.

Journal Article↗
PubMed1994

CD5-positive and CD5-negative plaque-forming cells against poly-L-lysine-treated sheep erythrocytes in patients with systemic lupus erythematosus.

While attempting to evaluate CD5+ and CD5- anti-DNA-secreting plaque-forming cells (PFC) in patients with systemic lupus erythematosus (SLE), significant numbers of PFC against control sheep erythrocytes (ShE) treated with poly-L-lysine (PLL) but not further conjugated with single-stranded (ss) or double-stranded (ds) DNA were noted. Numbers of PFC obtained using PLL-ShE, ssDNA-ShE and dsDNA-ShE were not significantly different, all reactivity to DNA apparently being accounted for by binding of antibodies to PLL-treated ShE. Nevertheless, anti-PLL-PFC could be inhibited by soluble dsDNA included in the plaque assay. These findings might be explained by cationic anti-DNA antibodies binding non-specifically to anionic PLL. Control healthy subjects gave few PFC against PLL-ShE, ssDNA-ShE or dsDNA-ShE. Anti-PLL-PFC appeared to be related to disease activity, with higher numbers of both CD5+ and CD5- PFC in patients with clinically active SLE.

Adolescent↗