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Biomedical subjects

I Gordon

Publications and source records attributed to I Gordon.

At least 19 recordsLinked to original sources
PubMed2006

3-D imaging and quantitative comparison of human dentitions and simulated bite marks.

This study presents a technique developed for 3-D imaging and quantitative comparison of human dentitions and simulated bite marks. A sample of 42 study models and the corresponding bites, made by the same subjects in acrylic dental wax, were digitised by laser scanning. This technique allows image comparison of a 3-D dentition with a 3-D bite mark, eliminating distortion due to perspective as experienced in conventional photography. Cartesian co-ordinates of a series of landmarks were used to describe the dentitions and bite marks, and a matrix was created to compare all possible combinations of matches and non-matches using cross-validation techniques. An algorithm, which estimated the probability of a dentition matching its corresponding bite mark, was developed. A receiver operating characteristic graph illustrated the relationship between values for specificity and sensitivity. This graph also showed for this sample that 15% of non-matches could not be distinguished from the true match, translating to a 15% probability of falsely convicting an innocent person.

Australia↗
PubMed2006

Bone mineralization in children with epidermolysis bullosa.

BACKGROUND: Various factors may have deleterious effects on bone health in patients with epidermolysis bullosa (EB). OBJECTIVES: In a retrospective notes review, to assess bone mineralization in children with EB and to identify the relative contributions of nutrition, activity and disease severity to low bone mass. METHODS: Thirty-nine children with EB [32 recessive dystrophic EB (RDEB), four Dowling-Meara EB simplex (DMEBS) and three junctional EB (JEB)] had lumbar spine bone mass measured using dual X-ray absorptiometry (GE Lunar Prodigy; GE Healthcare, Chalfont St Giles, U.K.). Seventy-six healthy children were also studied. Weight and height were recorded and mobility was rated. RESULTS: Children with RDEB and JEB, but not those with DMEBS, had lower bone mineral density SD scores than controls; differences remained after adjusting for the smaller body size of the patients. Bone mass was best predicted by mobility rating. CONCLUSIONS: Children with RDEB and JEB have low bone mass after adjusting for their smaller size, which may put them at risk for fragility fractures. Low bone mass was best predicted by the level of mobility, raising the hypothesis that improving activity or bone loading may be a potential preventive intervention in these children. However, as low bone mass may be multifactorial in these children, more detailed investigation of potential aetiological factors is required before interventions are planned.

Absorptiometry, Photon↗
PubMed2006

Laparoscopic versus open Burch colposuspension: a randomised controlled trial.

OBJECTIVE: To compare perioperative characteristics, short-term, and long-term outcomes for laparoscopic Burch colposuspension (LBC) and open Burch colposuspension (OBC) for the treatment of urinary stress incontinence. DESIGN: Randomised surgical trial with single blinding. SETTING: Three tertiary level teaching hospitals involving seven surgeons of varying skill levels. POPULATION: Two hundred women with urodynamic stress incontinence (USI). METHODS: The two groups were treated in identical fashion, except for the laparoscopic or open approach to surgery. Attempts were made to blind the subjects and the observers obtaining outcome data to treatment group. Analyses were adjusted for surgeon experience. MAIN OUTCOME MEASURES: Absence of USI 6 months following surgery, postoperative pain, time spent in hospital, and time to return to activities of normal daily living. RESULTS: There were no significant differences in objective and subjective measures of cure and in patient satisfaction at 6 months, 24 months, or 3-5 years of follow up between laparoscopic and open colposuspension groups. Laparoscopic colposuspension took longer time to perform (87 versus 42 minutes, P< 0.0001) but was associated with less blood loss (P = 0.03), less pain (P = 0.02), and quicker return to normal activities (P = 0.01). CONCLUSION: LBC has significant advantages over traditional OBC, without any apparent compromise in short-term and long-term outcomes. To compare perioperative characteristics, short-term, and long-term outcomes for laparoscopic Burch colposuspension (LBC) and open Burch colposuspension (OBC) for the treatment of urinary stress incontinence. Randomised surgical trial with single blinding. Three tertiary level teaching hospitals involving seven surgeons of varying skill levels. Two hundred women with urodynamic stress incontinence (USI). The two groups were treated in identical fashion, except for the laparoscopic or open approach to surgery. Attempts were made to blind the subjects and the observers obtaining outcome data to treatment group. Analyses were adjusted for surgeon experience. Absence of USI 6 months following surgery, postoperative pain, time spent in hospital, and time to return to activities of normal daily living. There were no significant differences in objective and subjective measures of cure and in patient satisfaction at 6 months, 24 months, or 3-5 years of follow up between laparoscopic and open colposuspension groups. Laparoscopic colposuspension took longer time to perform (87 versus 42 minutes, P < 0.0001) but was associated with less blood loss (P= 0.03), less pain (P= 0.02), and quicker return to normal activities (P= 0.01). LBC has significant advantages over traditional OBC, without any apparent compromise in short-term and long-term outcomes.

Female↗
PubMed2005

Dual X-ray absorptiometry (DXA) of the lumbar spine in a clinical paediatric setting: does the method of size-adjustment matter?

UNLABELLED: Dual X-ray absorptiometry (DXA) is increasingly used in a clinical setting to evaluate bone mass in children. Areal Bone Mineral Density (aBMD) measurements are known to be influenced by body size, but there is no consensus on the optimal way to deal with this for individual patients. AIM: To compare parameters of bone mass with varying degrees of size correction and to determine the effect on the categorisation of patients as normal or abnormal. SUBJECTS AND METHODS: Healthy children (n = 78) and 4 groups of patients (n = 194) underwent DXA scans of the lumbar spine (L2-4, GE Lunar Prodigy). Five measures of bone mass were derived, all adjusted for age and sex: aBMD, BMAD (BMC/BA (1.5)), BMCh (BMC/height3), BMCa (BMC adjusted for BA), BMCt (BMC adjusted for BA and height). SD scores were calculated for each parameter for patients using data from healthy controls. RESULTS: Compared to healthy children, all patient groups had significantly reduced BMD SD scores (P < 0.001). Mean BMAD, BMCa and BMCt SD scores were significantly lower in only 2/4 patient groups, whilst BMCh SD scores were low only in one group. BMCt showed no advantage over BMCa. The proportion of patients with SD scores <-2 was 27% for aBMD but between 10-13% for BMAD, BMCh and BMCa. CONCLUSIONS: All size-corrected parameters of bone mass performed similarly and classified significantly fewer patients as abnormal than did aBMD. The use of one of these parameters should reduce the number of patients diagnosed inappropriately with 'low bone mass'. However, without validation against an outcome measure or 'gold standard' of bone density or structure, it is not possible to determine which parameter is most correct.

Absorptiometry, Photon↗
PubMed2005

The presence of vesicoureteric reflux does not identify a population at risk for renal scarring following a first urinary tract infection.

BACKGROUND: Childhood urinary tract infection (UTI) with or without vesicoureteric reflux (VUR) may predispose to renal scarring. There is no clear consensus in the literature regarding imaging following UTI in infancy. AIMS: To define the role of cystography following a first UTI in children aged under 1 year, when urinary tract ultrasonography (US) is normal. METHODS: Retrospective data collection of 108 children (216 renal units) aged under 1 year at the time of a bacteriologically proven UTI. All had a normal US and underwent both catheter cystogram and DMSA test. Sensitivity, specificity, likelihood ratios positive and negative, and diagnostic odds ratio were calculated for VUR on cystography versus scarring on DMSA. RESULTS: VUR was shown in 25 (11.6%) renal units. Scarring on DMSA was seen in 8 (3.7 %) kidneys. Only 16% of kidneys with VUR had associated scarring; 50% of scarred kidneys were not associated with VUR. The likelihood ratio positive was 4.95 (95% CI 2.22 to 11.05) and the likelihood ratio negative was 0.56 (95% CI 0.28 to 1.11). The diagnostic odds ratio was 8.9, suggesting that cystography provided little additional information. CONCLUSION: Since only 16% of children with VUR had an abnormal kidney, the presence of VUR does not identify a susceptible population with an abnormal kidney on DMSA. In the context of a normal ultrasound examination, cystography contributes little to the management of children under the age of 1 year with a UTI. In this context, a normal DMSA study reinforces the redundancy of cystography.

Cicatrix↗
PubMed2004

Fourier transform infrared emission spectra of MgH and MgD.

High resolution Fourier transform infrared emission spectra of MgH and MgD have been recorded. The molecules were generated in an emission source that combines an electrical discharge with a high temperature furnace. Several vibration-rotation bands were observed for all six isotopomers in the X (2)Sigma(+) ground electronic state: v=1-->0 to 4-->3 for (24)MgH, v=1-->0 to 3-->2 for (25)MgH and (26)MgH, v=1-->0 to 5-->4 for (24)MgD, v=1-->0 to 4-->3 for (25)MgD and (26)MgD. The new data were combined with the previous ground state data, obtained from diode laser vibration-rotation measurements and pure rotation spectra, and spectroscopic constants were determined for the v=0 to 4 levels of (24)MgH and the v=0 to 5 levels of (24)MgD. In addition, Dunham constants and Born-Oppenheimer breakdown correction parameters were obtained in a combined fit of the six isotopomers. The equilibrium vibrational constants (omega(e)) for (24)MgH and (24)MgD were found to be 1492.776(7) cm(-1) and 1077.298(5) cm(-1), respectively, while the equilibrium rotational constants (B(e)) are 5.825 523(8) cm(-1) and 3.034 344(4) cm(-1). The associated equilibrium bond distances (r(e)) were determined to be 1.729 721(1) A for (24)MgH and 1.729 157(1) A for (24)MgD.

Journal Article↗
PubMed2004

Prenatally diagnosed unilateral renal pelvic dilatation: a dynamic condition on ultrasound and diuretic renography.

PURPOSE: Imaging characteristics obtained from serial scintigraphic and ultrasonographic studies in children with the prenatal diagnosis of unilateral pelvic dilatation are presented. MATERIALS AND METHODS: Serial ultrasonographic and scintigraphic findings in 101 children with unilateral pelvic dilatation collected during followup were reviewed. Changes in hydronephrotic kidney in terms of renal pelvis diameter, kidney size, differential renal function and drainage were noted. A total of 42 children underwent surgery at a mean age of 15.6 months (range 3.1 to 69.2, median 8.2), while 59 were treated nonsurgically. RESULTS: Mean age at presentation was 5.6 months (range 0.8 to 36.4, median 3.5). Mean followup was 35.5 months (range 6.4 to 78.4, median 29.6). Differential renal function remained stable (46.4% vs 47.3%) but improved drainage (68.4% vs 81.2%) and decreased renal pelvis size (22.2 vs 18.3 mm) was noted in the 2 groups. With age drainage function improved, especially between the younger than 12-month and 12-month or older groups. The mean affected-to-unaffected kidney length ratio at presentation was significantly greater than the ratio at the final followup (paired t test p <0.05). CONCLUSIONS: In this retrospective review drainage function was prolonged in infants. During followup drainage, dilatation and relative renal size improved in the surgery and nonsurgery groups. There was no change in renal function in either groups during followup. These data support the benign nature of prenatal unilateral hydronephrosis.

Age Factors↗
PubMed2003

Enhanced asymmetric magnetization reversal in nanoscale Co/CoO arrays: competition between exchange bias and magnetostatic coupling.

Magnetization reversal was studied in square arrays of square Co/CoO dots with lateral size varying between 200 and 900 nm. While reference nonpatterned Co/CoO films show the typical shift and increased width of the hysteresis loop due to exchange bias, the patterned samples reveal a pronounced size dependence. In particular, an anomaly appears in the upper branch of the magnetization cycle and becomes stronger as the dot size decreases. This anomaly, which is absent at room temperature in the patterned samples, can be understood in terms of a competition between magnetostatic interdot interaction and exchange anisotropy during the magnetic switching process.

Journal Article↗
PubMed2003

The significance of a defect on DMSA scan in children with renal transplants.

Since December 1995, pediatric renal transplant recipients in our unit have received a DMSA scan as soon as possible post-transplant in order to provide a baseline for comparison in the event of subsequent complications. We retrospectively reviewed the case notes and DMSA scans of the 45 patients who underwent a scan within 9 wk of their transplant to see if pre or peri-transplant factors or post-transplant complications were associated with defects on scanning. Forty percentage of scans had defects. The presence of defects was not associated with potential predisposing factors such as patient or donor age, cadaveric or live donation, cold ischemia time, multiple donor vessels, the use of non-heart beating donors, the mean time to scan, the serum creatinine, or the presence of structural renal tract anomalies predisposing to UTI. However, 87% of patients had complications before the scan, including UTI, rejection, acute tubular necrosis, transplant biopsy and drug toxicity. Children with no clinical complications had a significantly reduced risk of a defect (p = 0.035), while biopsy was associated with the presence of defects (p = 0.0034). Twenty patients had one or more follow up DMSA scans: one patient developed a new focal defect. In conclusion, renal transplant defects are frequently found on DMSA scanning even early after transplantation and are non-specifically associated with many different complications.

Adolescent↗
PubMed2003

Impaired drainage on diuretic renography using half-time or pelvic excretion efficiency is not a sign of obstruction in children with a prenatal diagnosis of unilateral renal pelvic dilatation.

PURPOSE: Delayed drainage on diuretic renography is an accepted sign of obstruction in adults and symptomatic children. We investigated how to analyze the diuretic challenge as well as assess the significance of impaired drainage. MATERIALS AND METHODS: We followed 24 children with a unilateral prenatal diagnosis of pelvic dilatation up to a minimum of 2 years. A total of 91 diuretic renograms were performed. All children had stable differential renal function and renal pelvic diameter did not change by greater than 9 mm. on sequential ultrasound. Kidneys with stable differential function and no increase in dilatation were considered not obstructed. Analysis of the diuretic challenge included half-time, a post-void image with a change in posture, that is the child erect for 5 to 7 minutes, and drainage considering renal function using the pelvic excretion efficiency. Prolonged drainage was defined as a half-time of greater than 20 minutes or a post-void pelvic excretion efficiency of less than 71%. RESULTS: Median patient age at presentation was 0.32 years and median followup was 3.07 years. The affected nonobstructed hydronephrotic kidney showed impaired drainage in 68% of the children using the half-time parameter, and in 80% and 44% using pelvic excretion efficiency before and after voiding, respectively. Variability in drainage was documented on sequential diuretic renography. CONCLUSIONS: Using the guidelines for data acquisition and processing of diuretic renograms we nevertheless noted impaired drainage in 44% of this young group with nonobstructed kidneys. The half-time parameter was an inappropriate parameter. The diagnosis of obstruction cannot be simply based on delayed drainage in this group of asymptomatic children with a prenatal diagnosis of unilateral renal pelvic dilatation.

Age Factors↗
PubMed2003

Non-invasive diagnosis of tracheobronchomalacia using a modified ventilation radioisotope lung scan.

The use of radionuclide ventilation lung scan to characterise the physiological effects of tracheobronchomalacia is a novel application of this non-invasive technique. In the reported case the right upper lobe was found to be not ventilated below a pressure of 20 cm H2O despite evidence from a dynamic tracheobronchogram of the right upper lobe bronchus opening at the lower pressure of 15 cm H2O.

Bronchial Diseases↗
PubMed2002

Assessment of regional kidney function may provide new clinical understanding and assist in treatment of children with prenatal hydronephrosis.

PURPOSE: As calculated from a (99m)technetium (Tc)-mercaptoacetyltriglycine (MAG3) renogram, differential renal function is an important parameter affecting the clinical treatment of children with prenatal unilateral hydronephrosis. We determined whether value is potentially added by calculating a functional image from MAG3 renograms that represents proximal tubule ability to clear tracer from the blood, that is the MAG3 clearance image. MATERIALS AND METHODS: MAG3 clearance image findings and differential renal function at presentation and followup in 59 nonsurgically and 42 surgically treated children with prenatally diagnosed unilateral hydronephrosis were retrospectively reviewed. All patients underwent at least 3 99mTc-MAG3 renograms. RESULTS: In the surgical and nonsurgical groups there was no significant difference in followup (p = 0.11), age at presentation (p = 0.98) or age at last visit (p = 0.97), whereas differential renal function was significantly different (p = 0.01). A large affected kidney with focal defects was the most frequent finding in each group, including kidneys with a normal differential renal function of 45% to 55%. In the nonsurgical group the most common observation was improvement in the MAG3 clearance image in 26 of 59 cases (44%) and stabilized differential renal function in 41 (70%). Postoperatively the MAG3 clearance image improved in 31 of 42 cases (74%) and differential renal function remained stable in 25 (60%), while no significant increase in differential renal function was noted at the last visit (p = 0.74). CONCLUSIONS: This study shows that it is possible to assess regional parenchymal function using the MAG3 clearance image in children with unilateral hydronephrosis. This information is available in addition to 99mTc-MAG3 information on the whole kidney, that is differential renal function. The majority of affected kidneys with normal differential renal function showed parenchymal defects, suggesting regional renal dysfunction. However, functional improvement on a regional basis occurred in each group of children during followup.

Child, Preschool↗
PubMed2002

Correlation of SPECT with pathology and seizure outcome in children undergoing epilepsy surgery.

SPECT can be used to image regional cerebral blood flow (rCBF) and has been shown to help localize the seizure focus in partial epilepsies as part of the presurgical evaluation. Few studies have explored the possible relation between preoperative SPECT and underlying pathology, or any relation to postsurgical outcome. In this study preoperative ictal and interictal rCBF in relation to the histopathological diagnosis and outcome in a series of 35 children (24 females, 11 males; mean age 9.6 years, age range 11 months to 18 years) who had undergone resective surgery for epilepsy were retrospectively evaluated. A correlation between ictal hyperperfusion and the underlying responsible pathology was shown, with a consistent ictal increase in perfusion in developmental pathologies and Rasmussen's encephalitis, and consistent interictal hypoperfusion in hippocampal sclerosis (HS). No rCBF study parameter appeared to relate to outcome but in the group with HS the best outcome was seen in those with localizing ictal rCBF. The varied group of pathologies from hemispherectomy had excellent outcome but the SPECT findings had little to contribute over the abnormalities detected on MRI. In conclusion, rCBF studies remain a useful presurgical investigation in children with partial epilepsy, especially where HS, cortical dysplasia, or inflammatory disease are the underlying pathology. However, rCBF studies add little to the investigation of children with seizures secondary to benign tumours or cerebral infarcts, or where hemispherectomy is the likely preferred surgical option.

Adolescent↗
PubMed2002

Effect of the size of regions of interest on the estimation of differential renal function in children with congenital hydronephrosis.

The estimation of differential renal function from dynamic renography affects clinical decisions. The estimation requires the kidneys to be delineated with regions of interest. However, in the presence of unilateral hydronephrosis it is not unusual for the affected kidney to be enlarged so that the regions of interest required to delineate the normal and abnormal kidneys are themselves dissimilar in size. The question, which then arises is, will this difference in the sizes of the regions of interest affect the resultant estimation of differential renal function? Eighteen children aged 1 month to 7 years, with prenatal ultrasound diagnosis of unilateral hydronephrosis where the affected kidney was larger than the normal kidney, underwent a total of 57 diuretic renograms using 99mTc-mercaptoacetyltriglycine. The renographic data were retrieved from optical disc and re-analysed. Regions of interest were generated which enclosed each kidney plus a region of interest of equal size to the abnormal large kidney was placed over the normal kidney. The consensus report from the Scientific Committee of Radionuclides in Nephrology described the Rutland-Patlak plot and integral methods for the estimation of differential renal function from dynamic renography. These two methods were used to analyse renal curves with and without background subtraction. Evaluation of the results suggest that technical factors, including the size of the region of interest, may affect differential renal function, and may, in part, explain the reports of the super-normal kidney in the literature.

Child↗
PubMed2001

Medical versus surgical treatment in children with severe bilateral vesicoureteric reflux and bilateral nephropathy: a randomised trial.

BACKGROUND: Nephropathy associated with vesicoureteric reflux (VUR) and urinary tract infection can result in end-stage renal failure, hypertension, or both. Whether long-term VUR contributes to these outcomes is unknown. We compared, in a randomised trial, medical with surgical management of children with bilateral severe VUR and bilateral nephropathy. METHODS: We stratified by age and glomerular filtration rate (GFR) 25 boys and 27 girls aged 1-12 years and randomly assigned them to medical or surgical management. At enrolment and 4 years' follow-up we estimated GFR from the plasma clearance of 51Cr-labelled edetic acid (EDTA), and did intravenous urography. We also did a metastable 99mTc-labelled dimercaptosuccinic acid (DMSA) assay and contrast cystography. The change in GFR at 4 years, expressed as a percentage change between enrolment and 4 years, was available for 26 of 27 patients in the medical and 24 of 25 in the surgical group. We assessed GFR in 48 patients 10 years after enrolment. FINDINGS: Mean GFR at enrolment was 72.4 mL/min per 1.73 m(2) (SD 24.1) in the medical and 71.7 mL/min per 1.73 m(2) (22.6) in the surgical group. The mean percentage change in GFR at 4 years was 2.4% (SE 4.5) versus 4.7% (5.0) in the medical and surgical groups, respectively. The difference in change in GFR at 4 years between the two groups was not significant (7.1%, 95% CI 6.4% to 20.6%). INTERPRETATION: Our data do not lend support to the view that the outcome for renal function is improved by surgical correction of VUR in children with bilateral disease.

Anti-Bacterial Agents↗
PubMed2001

Postnatal investigation of fetal renal disease.

The antenatal ultrasound diagnosis of renal tract abnormalities is now firmly established. Postnatal imaging protocols are constantly evolving and still many questions remain unanswered. Most infants are asymptomatic at birth and aggressive imaging is unwarranted both for the infant and overburdened Radiology departments. The urgency with which to undertake imaging relates to the suspected antenatal diagnosis and clinical scenario, with bilateral hydronephrosis, posterior urethral valves and complicated duplex systems taking a high priority. The main imaging modality postnatally remains ultrasound, and together with nuclear medicine gives a powerful combination of both anatomy and function. Intravenous urography is never indicated in the neonate.

Child↗