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Biomedical subjects

I Gordon

Publications and source records attributed to I Gordon.

At least 181 records · Page 10Linked to original sources
PubMed1990

Skeletal assessment in neuroblastoma--the pitfalls of iodine-123-MIBG scans.

This study was carried out to compare iodine-123 metaiodobenzylguanidine ([I123I]MIBG) and technetium-99m-methylene diphosphonate bone scans (99mTc-MDP) in the detection of skeletal involvement by neuroblastoma. Forty-four children with neuroblastoma underwent both [123I] MIBG and 99mTc-MDP scans within a 4-wk period; bone marrow examination also was performed; all these investigations were done both at diagnosis and at follow-up. At diagnosis, four children with Stage 4 disease had normal [123I]MIBG scans but abnormal 99mTc-MDP scans, while at follow-up there were four children with negative [123I]MIBG studies who later died from disseminated neuroblastoma. All eight scans are considered false-negative. In 24 children, the [123I]MIBG revealed more extensive disease with 161 positive sites while the 99mTc-MDP scan showed only 100 positive sites; 34 of these sites were common to both studies. This study shows that underassessment of skeletal involvement by neuroblastoma occurred using [123I]MIBG scans and that one cannot therefore substitute [123I]MIBG for 99mTc-MDP bone scans in the staging of neuroblastoma.

3-Iodobenzylguanidine↗
PubMed1989

Familial hypoplastic glomerulocystic kidney disease: a definite entity with dominant inheritance.

Autosomal dominant (or possibly X-linked) inheritance of familial hypoplastic glomerulocystic kidneys is described in a mother and son who both had stable, chronic renal failure, cystic kidneys by ultrasound examination, glomerular cysts as demonstrated histologically, and malformed renal calyces. There was no evidence of other congenital abnormalities apart from prognathism, small stature and pyloric stenosis. Hepatic fibrosis was not evident in a liver biopsy specimen. These findings add further confirmation to the existence of the syndrome of familial hypoplastic glomerulocystic kidney disease with dominant inheritance.

Adult↗
PubMed1989

Monoclonal antibodies as targeting agents for cytotoxic compounds in vivo: a current assessment.

Monoclonal antibodies have proved useful in the in vitro diagnosis of tumour type. Radiolabelled antibodies have also been investigated as targeting agents for the in vivo diagnosis of tumour metastasis. These studies have revealed the potential of using 'targeting agents' to identify tumours, but in addition have exposed some of the problems associated with the technique. This review describes our experiences using radiolabelled antibodies for the identification and treatment of tumours arising from the neuro-ectoderm. Based on a small number of 4 patients studies, we conclude that there are limitations on the use of radiolabelled antibodies for targeting isotopes to primary tumour masses. In addition, we outline a possible important role for antibodies in targeting therapeutic agents to minimal residual disease and diffuse tumours presenting as micro-metastasis.

Animals↗
PubMed1989

Multiple congenital abnormalities identifiable on 99Tcm HIDA scan.

We present a case in which three congenital abnormalities, in separate organ systems, were identifiable on a 99Tcm HIDA scan. The patient probably had Ivemark syndrome with dextrocardia (confirmed by chest radiograph), horseshoe kidney (confirmed by 99Tcm DTPA scintigraphy), and biliary atresia (confirmed on the HIDA scan). He also probably had asplenia, as suggested by the HIDA scan, although this was not confirmed.

Abnormalities, Multiple↗
PubMed1989

Social class as indicated by area of residence: a mortality study within an Australian industrial population.

The influence of social class on morbidity and mortality is well known and, in many epidemiological settings, its role as a potential confounding variable must be addressed. In occupational studies, particularly those based within a single industry, it is difficult to measure social class by scales based on occupational prestige. In a population study within the Australian petroleum industry, the all-cause mortality of males has been examined by social class, as indicated by area of residence, specifically, postcode. Rates of mortality were higher in the lower social classes, and the gradient was similar to that observed previously. The mortality rate of the lowest social class group relative to the highest was 1.73, and the test for trend was significant (p = 0.003). Whilst adjustment for smoking reduced the gradient somewhat, a social class effect remained.

Adult↗
PubMed1989

Effects of posture on the distribution of pulmonary ventilation and perfusion in children and adults.

In the adult the distributions of ventilation and of perfusion show the same directional dependence on gravity. In children, however, the distribution of ventilation in response to gravity is the reverse of that seen in adults. The aim of the current study was to determine whether perfusion showed the same reversal in children or followed the adult pattern. Distribution of perfusion was measured with intravenous technetium-99m macroaggregated albumin and distribution of ventilation with inhaled krypton-81m. Eighteen children and seven adults were studied; they had been referred for lung scanning for various respiratory problems. The effect of gravity was examined by giving aliquots of macroaggregated albumin and 81mKr by inhalation to the subject in the supine and the lateral decubitus position. Counts in the dependent lung were compared with those in the upper lung. The dependent lung in the lateral decubitus position received more of the total perfusion than it did in the supine position in seven children with a normal chest radiograph (mean 7.0%, range 4.8-10.9% more) and in 11 children with an abnormal radiograph (mean 3.4%(0.1-10.0%)). Ventilation, however, changed in the opposite direction, falling by 7.1% (-3.2% to -12.8%) in five children with a normal chest radiograph and 11.2% (-2.8% to -19.3%) in eight children with an abnormal radiograph. Fractional V/fractional Q (an index of the ventilation:perfusion ratio) decreased in the dependent lung in the children when they moved from the supine to the decubitus position. The same directional change was recorded in adults, but it was significantly less than in the children, irrespective of whether the chest radiograph was abnormal. In children and adults with various respiratory problems the effect of posture on the distribution of perfusion is similar.

Adult↗
PubMed1989

Spontaneous abrupt changes in the distribution of ventilation: a cause for apparent mismatching on ventilation/perfusion scintigraphy.

A defect seen in the perfusion scan in a region of lung that is normally ventilated is usually interpreted as indicating pulmonary vascular disease. Since the distribution of 99Tcm macro-aggregated albumin (MAA) represents the distribution of perfusion (Q) only at the time of MAA injection, the assumption is required that the distribution of ventilation (V) remains unchanged between MAA injection and the commencement of imaging. We report the V/Q scintigraphic findings in six patients (including four children), in whom this assumption could not be sustained. Thus ventilation imaged with 81Krm was seen to change during image acquisition in lobes that showed perfusion abnormalities. In some, but not all, views the appearances were typical for pulmonary vascular disease, which might easily have been misdiagnosed if the changes in the distribution of ventilation had not announced themselves by occurring during image acquisition. A ventilation image obtained immediately before injection of 99Tcm-MAA may be useful.

Child↗
PubMed1989

Streptokinase used in general practice.

Over a six-month study in general practice 43 patients were identified whose presenting symptom was chest pain thought to be cardiac in origin. The median time from the onset of pain to the general practitioner attending was 60 minutes. On the basis of history, examination and initial electrocardiogram these patients were assessed as unlikely or likely to be infarcting. Of this latter group 15 fulfilled the inclusion criteria for intravenous streptokinase, four commencing treatment at home and 11 on admission to the local general practitioner medical ward. Each received 1.5 mega units over 60 minutes. The median time from the onset of pain to the start of therapy was 120 minutes. Of the 28 patients clinically suspected of having sustained a myocardial infarct 24 proved positive--an over-diagnosis rate of 14%. No major problems were encountered following streptokinase.

Emergencies↗
PubMed1988

Two routes for 99mTc-DMSA uptake into the renal cortical tubular cell.

Critical factors determining the renal handling of 99mTc-dimercaptosuccinic acid (DMSA) are protein binding in plasma and the renal 99mTc-DMSA extraction efficiency. Comparison of the count rate over soft tissue with that over the cardiac blood pool about 1 h after injection demonstrated that 99mTc-DMSA is not exclusively an intravascular label. 99mTc-DMSA was 76% protein bound in plasma as demonstrated by HPLC and gel filtration. Assuming that the 24% that is not protein bound is filtered at the glomerulus, the renal extraction efficiency of 99mTc-DMSA by glomerular filtration is about 5%. Since the total renal extraction efficiency was also found to be about 5%, the majority of the activity that becomes fixed in the renal cortex arrives there as a result of filtration followed by tubular reabsorption rather than by direct extraction from peritubular blood. However, discordant changes in DMSA and DTPA uptake induced by captopril in renovascular hypertension (RVH) suggested that a minority of uptake was by direct peritubular extraction. This kinetic model was supported by indirect measurement of protein binding and extraction efficiency based on the kinetics of 99mTc-DMSA disappearance from plasma and kinetics of uptake in the kidneys. Furthermore, differential functional studies based on 99mTc-DMSA and 99mTc-DTPA before and after captopril in patients with RVH due to unilateral renal artery stenosis confirmed filtration followed by tubular reabsorption as the predominant route for DMSA uptake by the kidney.

Adult↗
PubMed1988

The biodistribution and pharmacokinetics of meta-iodobenzylguanidine in childhood neuroblastoma.

MIBG is generating considerable interest for the treatment of neuroblastoma. This study has investigated the biological variation in handling of the compound in children with neuroblastoma. The biodistribution of the compound has been characterised in children undergoing tracer administrations of 123I and 131I-mIBG. Estimates of hepatic and whole body radiation dose delivery have been made. The results indicate substantial interpatient variation in hepatic dose delivery. This organ may be critical in some patients undergoing targeted radiotherapy with mIBG.

3-Iodobenzylguanidine↗
PubMed1988

Superovulation and oocyte recovery in the ewe.

Thirty-eight adult ewes were superovulated following a 12 d progestagen treatment in association with either 135 mg crude horse anterior pituitary extract (HAP) or 30 mg soluble HAP with or without 1000 IU human chorionic gonadotrophin (hCG). Soluble HAP in combination with hCG significantly (P < 0.01) increased the ovulation rate as compared to HAP alone (14.5 vs 5.3, respectively). The number of oocytes recovered per ewe showing estrus following soluble HAP and HCG (6.9) was higher than after HAP alone (3.3), but this difference was not significant. A significantly higher (P < 0.05) ovulation rate and ovarian response were obtained following crude HAP than soluble HAP (14.0 vs 6.3 and 15.3 vs 9.4, respectively). There was a tendency for the proportion of follicles which ovulated to be higher in the crude HAP group. The mean number of oocytes or the proportion of oocytes recovered was significantly higher (P < 0.05) in the crude HAP group than in the soluble HAP group.

Journal Article↗
PubMed1988

Interdistrict migration in Great Britain 1980-81: a multistream model with a commuting option.

"In this paper an existing three-stream model of migration is adopted and extended to provide a first representation of district-district flows within Great Britain in 1980-81. The extended model incorporates an option for prospective migrants to choose commuting rather than a residential move after finding a new workplace, and employs a logistic function of distance in the regional or environmental stream where migrational opportunities tend not to be independent. Results are presented for the distribution of flows between local, regional, and national streams and for the geographical pattern of pushes and pulls in each."

Behavior↗
PubMed1988

Background in 99Tcm DTPA renography evaluated by the impact of its components on individual kidney glomerular filtration rate.

Following injection for renography, 99Tcm-labelled diethylenetriamine-pentacetic acid (DTPA) rapidly enters the extravascular space. Background therefore comprises two components, a falling intravascular signal and an extravascular signal which initially rises. We estimated the relative magnitudes of these two components in terms of their impact on the calculation of differential renal function and individual kidney glomerular filtration rate (IKGFR) from the second phase of the 99Tcm-labelled DTPA renogram in 56 paediatric kidneys. We expressed each of the two background signals as a GFR equivalent. The GFR equivalent of the intravascular signal recorded from a peri-renal background region of interest (ROI), scaled by a factor equal to the ratio of the pixel numbers in the renal and background ROIs, was -39 (S.D. 14) ml min-1. The GFR equivalent of the extravascular signal was smaller than this and opposite to it at 23 (S.D. 10) ml min-1, giving a median ratio for the two equivalents of -1.68. Because of the opposing effects of the two background components on the second phase of the renogram, techniques recently described for the quantification of IKGFR from the renogram, and which eliminate the intravascular component, offer no theoretical advantage over a method of analysis which uses 'direct' subtraction of the total background signal. In practice, however, these new techniques are superior in their handling of 'noisy' data, consistently giving a lower coefficient of variation in their estimation of IKGFR.

Child↗