Biomedical subjects

Peter J Anderson

Publications and source records attributed to Peter J Anderson.

At least 19 recordsLinked to original sources

PubMed2006

Neonatal MRI to predict neurodevelopmental outcomes in preterm infants.

BACKGROUND: Very preterm infants are at high risk for adverse neurodevelopmental outcomes. Magnetic resonance imaging (MRI) has been proposed as a means of predicting neurodevelopmental outcomes in this population. METHODS: We studied 167 very preterm infants (gestational age at birth, 30 weeks or less) to assess the associations between qualitatively defined white-matter and gray-matter abnormalities on MRI at term equivalent (gestational age of 40 weeks) and the risks of severe cognitive delay, severe psychomotor delay, cerebral palsy, and neurosensory (hearing or visual) impairment at 2 years of age (corrected for prematurity). RESULTS: At two years of age, 17 percent of infants had severe cognitive delay, 10 percent had severe psychomotor delay, 10 percent had cerebral palsy, and 11 percent had neurosensory impairment. Moderate-to-severe cerebral white-matter abnormalities present in 21 percent of infants at term equivalent were predictive of the following adverse outcomes at two years of age: cognitive delay (odds ratio, 3.6; 95 percent confidence interval, 1.5 to 8.7), motor delay (odds ratio, 10.3; 95 percent confidence interval, 3.5 to 30.8), cerebral palsy (odds ratio, 9.6; 95 percent confidence interval, 3.2 to 28.3), and neurosensory impairment (odds ratio, 4.2; 95 percent confidence interval, 1.6 to 11.3). Gray-matter abnormalities (present in 49 percent of infants) were also associated, but less strongly, with cognitive delay, motor delay, and cerebral palsy. Moderate-to-severe white-matter abnormalities on MRI were significant predictors of severe motor delay and cerebral palsy after adjustment for other measures during the neonatal period, including findings on cranial ultrasonography. CONCLUSIONS: Abnormal findings on MRI at term equivalent in very preterm infants strongly predict adverse neurodevelopmental outcomes at two years of age. These findings suggest a role for MRI at term equivalent in risk stratification for these infants.

Brain↗

PubMed2006

Reduction in cerebellar volumes in preterm infants: relationship to white matter injury and neurodevelopment at two years of age.

A substantial number of prematurely born infants will experience later neurodevelopmental challenges. Abnormal development of the cerebellum may be related to some of the impairments exhibited by preterm children. To test the hypothesis that cerebellar development is structurally impaired in preterm infants and associated with adverse outcomes, we studied 83 preterm infants and 13 term controls using volumetric magnetic resonance imaging techniques to obtain cerebellar volumes (CV) at term corrected and subsequent neurodevelopmental assessment at 2 y of age. The preterm group had smaller mean CV at term compared with the term control infants [mean (SD) CV, 22.0 (5.0) versus 23.5 (5.0) cc; mean difference (95% confidence interval), 1.5 (-1.5, 4.4)] although this did not reach statistical significance. Within the preterm group, there was evidence of a reduction in CV related to the presence of white matter injury (WMI) after adjusting for intracranial volume (ICV) [WMI grade 1 versus grade 2: mean (SD) CV, 23.6 (5.0) versus 21.6 (4.5); p = 0.01; WMI grade 1 versus grade 3 and 4: 23.6 (5.0) versus 20.8 (5.6); p = 0.07]. Within the preterm infants, there was no apparent relationship between CV at term and gestational age at birth after adjusting for ICV. At 2 y of age, CV showed a weak correlation with cognitive and motor development, although this was principally mediated by WMI. In conclusion, we found no evidence for a primary impairment in cerebellar development in relation to prematurity, although there was evidence for a secondary effect of cerebral WMI on cerebellar development independent of immaturity.

Aging↗

PubMed2006

Robustness of estimation of differential renal function in infants and children with unilateral prenatal diagnosis of a hydronephrotic kidney on dynamic renography: How real is the supranormal kidney?

PURPOSE: The two methods recommended for estimation of differential renal function (DRF) in the renography guidelines published by the European Association of Nuclear Medicine are the area under the background-subtracted time-activity curves (AUCs) (often called the integral method) and the regression slope of the background-subtracted Rutland/Patlak plot analysis. The current study investigated the agreement/disagreement of DRF estimations obtained using these two techniques. This report also focusses on the occurrence of supranormal function of the affected kidney (defined as DRF >55%) and reviews the related technical and physiological factors. METHODS: A total of 394 renographic studies in 101 children with a prenatal diagnosis of unilateral renal pelvic dilatation confirmed on postnatal studies were retrieved from optical disc and reprocessed by one author. DRF was calculated using the Rutland/Patlak plot and the AUC over the time period 40-120 s following an injection of( 99m)Tc-mercaptoacetyltriglycine. The difference in DRF between the methods (Rutland/Patlak minus AUC) and 95% limits of agreement were calculated. The age distribution of the difference between the methods was also analysed. RESULTS: For all 394 measurements the mean difference was -0.8% (range -21.0% to 16.9%, SD 3.9%). The 95% limits of agreement were -7.0% to 8.6%. Analysis of the data revealed that greater spread of DRF between the techniques was seen in studies performed at a younger age: a discrepancy of >5% DRF was significantly more common in those <1 year of age than in those >1 year old (25.3% vs 9.9%; chi-square, p<0.0005). Supranormal function was found less frequently using the Rutland/Patlak method than with the AUC method (8.4% vs 11.2%; chi-square, p<0.0005). The frequency of this diagnosis was reduced to 4.6% when both methods were required to be in agreement. CONCLUSION: The current study supports the existence of age-related variation in the disparity of DRF estimations using the AUC and Rutland/Patlak methods in children with unilateral pelvic dilatation. The close agreement between the AUC and Rutland/Patlak techniques in estimation of DRF in older children supports their use. However, careful quality control of the renogram analysis is essential in young babies. Supranormal renal function (>55% DRF) may in fact be much less common in this group of children than is currently reported.

Child↗

PubMed2006

Human vitamin B12 absorption measurement by accelerator mass spectrometry using specifically labeled (14)C-cobalamin.

There is a need for an improved test of human ability to assimilate dietary vitamin B(12). Assaying and understanding absorption and uptake of B(12) is important because defects can lead to hematological and neurological complications. Accelerator mass spectrometry is uniquely suited for assessing absorption and kinetics of carbon-14 ((14)C)-labeled substances after oral ingestion because it is more sensitive than decay counting and can measure levels of (14)C in microliter volumes of biological samples with negligible exposure of subjects to radioactivity. The test we describe employs amounts of B(12) in the range of normal dietary intake. The B(12) used was quantitatively labeled with (14)C at one particular atom of the dimethylbenzimidazole (DMB) moiety by exploiting idiosyncrasies of Salmonella metabolism. To grow aerobically on ethanolamine, Salmonella enterica must be provided with either preformed B(12) or two of its precursors, cobinamide and DMB. When provided with (14)C-DMB specifically labeled in the C2 position, cells produced (14)C-B(12) of high specific activity (2.1 GBq/mmol, 58 mCi/mmol) (1 Ci = 37 GBq) and no detectable dilution of label from endogenous DMB synthesis. In a human kinetic study, a physiological dose (1.5 microg, 2.2 kBq/59 nCi) of purified (14)C-B(12) was administered and showed plasma appearance and clearance curves consistent with the predicted behavior of the pure vitamin. This method opens new avenues for study of B(12) assimilation.

Carbon Radioisotopes↗

PubMed2006

Sinorhizobium meliloti bluB is necessary for production of 5,6-dimethylbenzimidazole, the lower ligand of B12.

An insight into a previously unknown step in B(12) biosynthesis was unexpectedly obtained through our analysis of a mutant of the symbiotic nitrogen fixing bacterium Sinorhizobium meliloti. This mutant was identified based on its unusually bright fluorescence on plates containing the succinoglycan binding dye calcofluor. The mutant contains a Tn5 insertion in a gene that has not been characterized previously in S. meliloti. The closest known homolog is the bluB gene of Rhodobacter capsulatus, which is implicated in the biosynthesis of B(12) (cobalamin). The S. meliloti bluB mutant is unable to grow in minimal media and fails to establish a symbiosis with alfalfa, and these defects can be rescued by the addition of vitamin B(12) (cyanocobalamin) or the lower ligand of cobalamin, 5,6-dimethylbenzimidazole (DMB). Biochemical analysis demonstrated that the bluB mutant does not produce cobalamin unless DMB is supplied. Sequence comparison suggests that BluB is a member of the NADH/flavin mononucleotide (FMN)-dependent nitroreductase family, and we propose that it is involved in the conversion of FMN to DMB.

Benzimidazoles↗

PubMed2006

Spectrum of features in pterygium syndrome.

Pterygium syndrome is a complex and rare congenital deformity that consists of contractures involving multiple flexural surfaces and associated craniofacial anomalies. It often has associated conditions, including anomalies of the cardiovascular, respiratory, gastrointestinal and genitourinary systems. It may present in different forms, including multiple pterygium syndrome of Escobar, lethal multiple pterygium syndrome, popliteal pterygium syndrome, lethal popliteal syndrome (Bartsocas-Papas syndrome) and arthrogryposis multiplex congenita. The clinical presentation, multidisciplinary management and the long-term outcome in three patients with this condition are presented.

Abnormalities, Multiple↗

PubMed2006

Neurodevelopmental outcome of bronchopulmonary dysplasia.

Children born very preterm are vulnerable for long-term cognitive, educational, and behavioral impairments; bronchopulmonary dysplasia (BPD) is an additional risk factor which exacerbates these problems. As a population, children with BPD exhibit low average IQ, academic difficulties, delayed speech and language development, visual-motor integration impairments, and behavior problems. Neuropsychological studies are sparse, but there is some evidence that children with BPD also display attention problems, memory and learning deficits, and executive dysfunction. BPD does not appear to be associated with a specific neuropsychological impairment but rather a global impairment.

Bronchopulmonary Dysplasia↗

PubMed2006

From birth to maturity: a group of patients who have completed their protocol management. Part II. Isolated cleft palate.

BACKGROUND: The optimal management of the cleft palate patient from birth to completion of treatment continues to present a formidable challenge to the plastic surgeon. The management by multidisciplinary teams is well established, but long-term outcome data of cases managed by protocol remain sparse. This study continues to present the results of the Australian Craniofacial Unit of patients with isolated cleft palate who completed protocol management at the unit under the care of the senior author (D.J.D.) during the 29-year period from 1974 to 2003. METHODS: A retrospective study of the outcomes in relation to facial growth, speech, hearing, and occlusion is presented of patients with an isolated cleft palate. RESULTS: Thirty-two cases were identified from the departmental database, involving 17 female patients and 15 male patients. Cephalometric analysis at skeletal maturity revealed a range of facial growth, and maxillary advancement surgery was deemed necessary in just two cases. Speech results were evaluated using speech therapy assessments during development and at maturity. At maturity, 18 of 32 patients were assessed as being within normal limits. The hearing was within -20 dB, with just two exceptions. CONCLUSION: Overall, these is a range of outcomes, but the results confirm that facial growth does not appear to be adversely affected by use of the pushback technique to reconstruct the palate.

Articulation Disorders↗

PubMed2006

Pyrexia after transcranial surgery.

Pyrexia after transcranial surgery has been observed regularly in clinical practice but does not usually herald any subsequent pathologic process. However, the significance and incidence of this phenomenon remain uncertain. The aim of this study was to evaluate the incidence and timing of any pyrexia after transcranial surgery for craniosynostosis correction and correlate this with the clinical outcome to assess its significance. Retrospective review of sequential case notes collected over a 10 year period identified 136 transcranial operations undertaken for 122 cases of nonsyndromic craniosynostosis. The incidence of postoperative pyrexia of 38 degrees or more in the first 5 days was 76%, whereas that greater than 39 degrees was 11%. Pyrexia was noticed during the first 48 hours and had a bimodal distribution. Only a single case in this series subsequently developed a clinically significant complication, that is, a minor wound infection of the skin, which was treated by antibiotics and dressings. The occurrence of pyrexia did not appear to be related either to sex or to any affected suture but occurred less frequently in those who were under 6 months old. We conclude that this pyrexia should be considered to be a part of the normal physiological response to craniofacial surgery.

Adolescent↗

PubMed2006

Scanning electron microscope and micro-CT evaluation of cranial sutures in health and disease.

Current knowledge of suture biology has been ascertained as a result of morphological studies of normal cranial sutures (and rarely those undergoing craniosynostosis). These were initially undertaken often using histological investigations, or more recently using CT scans, as investigative tools, but have often used animal models. However, recent technological advances have provided the potential to refine our understanding of the ultrastructure by the use of new advanced scanning technology, which offers the possibility of more detailed resolution. Our aim was to undertake detailed scans of normal, fusing and fused sutures from patients with craniosynosotosis affecting different sutures, to study the detailed structure at different stages of the fusion process using a modern micro-CT scanner and a microanalytical scanning electron microscope. We wished to include in our study all the human sutures because previous studies have mostly been undertaken using the sagittal suture. Ten sutures from seven patients have revealed a complex ultra-structural arrangement. The different patterns of bone ridging seen on the ectocranial and endocranial surfaces of the fused sagittal suture were not repeated on closer inspection of either fused coronal or lambdoid sutures. Elemental analysis confirmed that the amount of calcium increased and the amount of carbon decreased as sampled areas moved away from the suture margin. We conclude that scanning allowed detailed assessment and revealed the complex arrangement of the structure of the human cranial sutures and those undergoing the process of craniosynostosis, with some differences in final structure depending on the affected suture.

Child, Preschool↗

PubMed2006

A three-dimensional computed tomographic analysis of the cervical spine in unoperated infants with cleft lip and palate.

OBJECTIVE: To investigate anatomical variations and abnormalities of cervical spine morphology in unoperated infants with cleft lip and palate. DESIGN: Retrospective cross-sectional investigation of infants born with nonsyndromic cleft lip and palate using computed tomography scans acquired for investigation of a spectrum of clinical conditions. SETTING: Computed tomography scan data were obtained from 29 unoperated cleft lip and palate infants and 12 noncleft infants of Malay origin, ages 0 to 12 months. METHODS: Observational study of cervical spine computed tomography scans. Heights of cervical vertebral bodies (C2-C7) and intervertebral spaces were measured from landmarks identified from computed tomography reformats and three-dimensional computed tomography reconstructions. Linear modeling of heights and spaces, with age as a covariate, was undertaken to identify differences between the samples. RESULTS: Anomalous features observed in the cleft lip and palate sample included short posterior arch of C1 (2/29), abnormal development of the anterior arch of C1 (2/29), and fusions of the posterior arch of C2 and C3 (2/29). No anomalies of the cervical spine were observed in the noncleft sample. Although the heights of three cervical vertebral bodies were significantly smaller and two intervertebral spaces were significantly larger in infants with cleft lip and palate compared with noncleft infants (p < .05), overall length of the cervical spine did not differ significantly between the samples. CONCLUSION: There was evidence for subtle upper spinal anomalies in the infant cleft lip and palate population. Our finding of reduced size of some cervical vertebral bodies may reflect delayed upper spinal development in infants with cleft lip and palate.

Cervical Vertebrae↗

PubMed2006

The hyoid bone in malay infants with cleft lip and palate.

OBJECTIVE: To compare morphological and positional variations of the hyoid bone in unoperated infants with cleft lip and palate (CL/P) with those in noncleft infants. DESIGN: Retrospective, cross sectional. PATIENTS AND METHODS: Three-dimensional computed tomography scans were obtained from 29 unoperated CL/P infants of Malay origin aged between 0 and 12 months and from 12 noncleft infants in the same age range. Observations were made and measurements were obtained with a software package developed at the Australian Craniofacial Unit. The sizes of the hyoid bones and the position of the hyoid body and epiglottis in relation to the cervical spine were measured. Anatomical anomalies of the hyoid and prevalence of aspiration pneumonia were also documented. RESULTS: The hyoid bones and epiglottis were found to be located more inferiorly in CL/P infants compared with the noncleft infants. Also, 17% (5/29) of the CL/P infants had nonossified hyoid bodies. CONCLUSION: The results suggest that there are differences in the location and genesis of the hyoid bone in infants with CL/P that warrant further investigation.

Age Distribution↗

PubMed2005

Hyperostosis as a late sequel of parasymphyseal mandibular fractures in 2 children.

BACKGROUND: The potential problem of growth anomalies affecting a mandible following a fracture of a mandibular condyle in childhood is well established. However, there have been no previous reports of this phenomenon affecting other fracture sites in the mandible. PATIENTS: Two patients who had parasymphyseal fractures treated in childhood presented at skeletal maturity with hyperostosis at the fracture site, producing chin asymmetry in their teens. RESULTS: In both cases the hyperostosis produced significant chin asymmetry without disturbance of the occlusion. Both patients were managed with corrective genioplasty. CONCLUSION: These cases reinforce the previous recommendations regarding the need for long-term follow-up of children who sustain facial fractures of the mandible, and that the protocol should be expanded to include parasymphyseal fractures as well as fractures of the condyle.

Accidents, Traffic↗

PubMed2005

Simultaneous multiple vector distraction for craniosynostosis syndromes.

Syndromic craniosynostoses are commonly treated conditions in craniofacial units. The features of the common syndromes (Apert, Pfeiffer and Crouzon) all include craniosynostosis, mid-face hypoplasia and ocular proptosis. The craniofacial management of a child with these syndromes through to adulthood may require a number of surgical interventions to allow brain development, to provide an adequate airway, to prevent corneal ulceration and to provide a functional dental occlusion. The management of these different priorities into timed interventions in our unit is determined by established protocols. We report two cases that underwent simultaneous mid-face (Le Fort III) and fronto-orbital osteotomies followed by distraction but using different vectors to advance the upper and mid-face regions (to achieve all treatment goals) in a 12-year-old boy and a 16-year-old girl.

Acrocephalosyndactylia↗

PubMed2005

Familial Parry-Romberg disease.

Parry-Romberg disease (or hemifacial atrophy) is a rare condition affecting the face. It commences in childhood but its aetiology remains unknown, and is sporadic. Two cases are presented who were biological first cousins. We believe that this is the first recorded example of this condition occurring in family members.

Adolescent↗

PubMed2005

Ophthalmic sequelae of Crouzon syndrome.

PURPOSE: To document the frequency of ophthalmic sequelae in patients with Crouzon syndrome before the influence of craniofacial surgery. DESIGN: Retrospective observational case series. PARTICIPANTS: Seventy-one consecutive patients with a clinical diagnosis of Crouzon syndrome assessed before craniofacial or ophthalmic surgery at the Australian Craniofacial Unit between 1984 and 2000. METHODS: Review of clinical records with documentation of patient age, gender, visual acuity, refractive error, diagnosis of amblyopia, squint, eye movement dysfunction, nystagmus, fundus examination, examination of the anterior segment, interpupillary distance, and intercanthal distance. MAIN OUTCOME MEASURES: The frequency of ophthalmic signs and visual impairment, defined as a visual acuity of 6/12 or less. RESULTS: Visual impairment in at least 1 eye occurred in 35% of patients and was bilateral in 9%. The most common cause of visual impairment was amblyopia, which was present in 21% of patients, followed by optic atrophy in 7%. Ametropia occurred in 77% of patients; 57% had hypermetropia of > or =+2 diopters (D) and 20% had myopia of > or =-0.5 D. Strabismus occurred in 39% of patients. Although exposure keratopathy was observed in 15% of patients, this complication was well managed and caused no reduction in visual acuity. CONCLUSIONS: Early detection to reduce amblyopia by correction of refractive errors, timely treatment of strabismus, and patching should be a priority for ophthalmologists and a goal of the craniofacial teams managing patients with Crouzon syndrome. Optic atrophy remains an important cause of visual impairment in these patients before decompressive craniectomy.

Adolescent↗

PubMed2005

Late results after unicoronal craniosynostosis correction.

The authors report nine patients with unicoronal synostosis who were treated with the same surgical protocol and who now have reached skeletal maturity. These patients all underwent surgery at the Australian Craniofacial Unit during a 2-year period by one of two craniofacial surgeons and one of two neurosurgeons. The operative procedure in all of these cases was the same technique, in which there was unilateral advancement of the affected side. No cases required reoperation; however, one case subsequently required revision of the coronal scar, and two cases required strabismus correction. All cases were reviewed to evaluate patient results by the clinical staff; recent photographs at skeletal maturity also were reviewed. Two patients had adult computed tomography scans available for skeletal assessment, and one additional patient had undergone serial computed tomography scans during childhood. The patients also completed an anonymous questionnaire to ascertain their assessment of their appearance. The results of the clinical and radiologic assessments and questionnaire suggest that the operative procedure undertaken in these cases has produced satisfactory results in the long term, with few individuals requiring (or even considering) additional surgery, despite some persistent asymmetry.

Adult↗

PubMed2005

Spinal anomalies in Goldenhar syndrome.

OBJECTIVE: Goldenhar syndrome consists of the triad of craniofacial microsomia, occular dermoid cysts, and spinal anomalies. The exact nature of the spinal anomalies remains poorly defined in the existing craniofacial literature, possibly due to these anomalies being managed by orthopedic surgeons rather than by craniofacial surgeons. The aim of this study was to clarify the nature and extent of these spinal anomalies. METHOD: Review of case notes of patients who had their diagnosis confirmed following review by a clinical geneticist and in conjunction with radiographs (supplemented by three-dimensional computed tomographic [CT] scans where available). RESULTS: Seven patients fulfilled the entry criteria and had material available for study. A wide range of anomalies was present, including butterfly vertebrae; hemivertebrae, which produced secondary scoliosis; kyphosis; and rib anomalies. Anomalies occurred at all levels within the spine. CONCLUSION: The possibility of spinal anomalies at all levels of the spine should be considered by those treating cases of Goldenhar syndrome, because these anomalies cannot be predicted from the severity of the facial malformation.

Adolescent↗