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Biomedical subjects

I Gordon

Publications and source records attributed to I Gordon.

At least 217 records · Page 12Linked to original sources
PubMed1987

99mTc DTPA scintigraphy compared with intravenous urography in the follow-up of posterior urethral valves.

Twenty-seven patients with posterior urethral valves with varying degrees of renal function underwent both intravenous urography (IVU) and DTPA scan during their follow-up. Although the IVU was successful in excluding obstruction in 31 kidneys, the DTPA scan was successful in 43 kidneys. In addition, the DTPA scan provides quantifiable renal function, exposes the child to a lower radiation dose and has no morbidity compared with an IVU. It is recommended that the DTPA scan should replace the IVU for long-term follow-up and that the latter should be reserved for certain problems.

Child↗
PubMed1987

Background in the 99mTc DTPA renogram: analysis of intravascular and extravascular components.

Individual kidney glomerular filtration rate (IKGFR) was calculated from the upslope of the 99mTc-diethylenetriamine pentaacetic acid (DTPA) renogram in ten children with a normal solitary kidney (on the right in five and on the left in five). By using a method of renogram analysis that is independent of the intravascular (IV) component of background (BG) activity, the IV and extravascular (EV) components of background were separately quantified in various regions in proximity to the nephrectomy site. The size of the IV compartment was expressed as an absolute plasma volume (PV-BG), and that of the EV compartment was expressed as a "GFR equivalent," i.e., the undirectional rate of fluid transfer from the IV to EV spaces in ml per min (GFR-BG). The region areas from which these parameters were calculated were normalised to the area projected by the solitary kidney. In a region centred over the lower pole of the imagined absent kidney, PV-BG was 129 +/- 7 ml (SE) and GFR-BG was 28 +/- 1.8 ml per min. The corresponding values centred over the liver/spleen on the nephrectomised side were 353 +/- 24 ml and -2 +/- 2.9 ml per min, respectively. PV-BG, but not GFR-BG, was significantly higher over the liver (397 ml and -6.8 +/- 1.5 ml per min) compared with the spleen (287 ml, P less than .05; and 4.5 +/- 3.2 ml per min, P greater than .05). PV-BG and GFR-BG in a region placed over the centre of the nephrectomy site were intermediate between those superior and inferior: 231 +/- 17 ml and 15 +/- 2.7 ml per min, respectively. The IV signal rises while the EV falls during the second phase of the renogram. In the analysis of the renogram during this phase, therefore, background should be based on both supra- and subrenal regions of interest.

Child↗
PubMed1987

Therapeutic application of radiolabeled monoclonal antibody UJ13A in children with disseminated neuroblastoma.

Dosimetric data from UJ13A scanning studies using 131I are presented for children with stage IV neuroblastoma and primary brain tumor. The data demonstrate a large variation among patients in dose delivery to vulnerable organs and tumors. Against this background, a phase I toxicity study is under way with escalating amounts of conjugate administered to patients who have stage IV neuroblastoma. Major toxicity has been confined to bone marrow aplasia and necessitates bone marrow harvest prior to therapy. Specific problems encountered include altered kinetics during therapy following tracer studies and adequate dose delivery in large tumor masses.

Antibodies, Monoclonal↗
PubMed1986

Smoking in an industrial population. An analysis by birth cohort.

Between 1981 and 1984, 10,923 male and 624 female employees of the Australian petroleum industry were interviewed and the information that was collected included a detailed life-time smoking history. Comparison with another survey suggested that, in terms of smoking habits at least, this industrial population did not differ substantially from the general population. On the assumption that reasons for entering and leaving the industry are unconnected with smoking habit, the data were analysed by birth cohorts. In men, each successive generation has contained fewer smokers at every age over 20 years and this is due both to a reduction in the rate of starting to smoke, and to an increase in the cessation rates. In the case of women, the situation is reversed, and successive generations show an increasing prevalence and increasing starting rates.

Adolescent↗
PubMed1986

Clinical, haematological, and radiological features in T-cell lymphoblastic malignancy in childhood.

T-cell lymphoblastic malignancy in childhood includes both T-cell acute lymphoblastic leukemia (T-ALL) and non-Hodgkin's lymphoblastic lymphoma (T-NHL). There is considerable overlap between these disorders, which probably represent two ends of the same disease spectrum. To determine whether there are radiological differences between T-ALL and T-NHL we reviewed the clinical, haematological and radiological features of 58 children seen in one centre over a 9-year period. Splenomegaly and adenopathy were significantly more common in T-ALL than in T-NHL. Patients with T-ALL were usually anaemic and thrombocytopenic, with elevated white blood cell counts; patients with T-NHL had normal blood counts. The radiological abnormalities seen were mediastinal enlargement, pleural effusions, and tracheal compression. All patients with T-NHL had abnormal chest radiographs, whereas 10 of 39 patients with T-ALL had normal chest radiographs. When only abnormal radiographs were compared, however, there were no differences in the degree of mediastinal widening or in the size of pleural effusions. Tracheal compression was more common in T-NHL and was always most marked in the intrathoracic airway and in an antero-posterior direction. We conclude that there is little difference in the radiological abnormalities seen in T-ALL and T-NHL, which further supports the theory that they represent points along a common spectrum of disease. As airway compression is primarily intrathoracic and in an antero-posterior direction, adequate radiological evaluation should include a lateral chest radiograph.

Adolescent↗
PubMed1986

131-I coupled to monoclonal antibodies as therapeutic agents for neuroectodermally derived tumors: fact or fiction?

It has been suggested that monoclonal antibodies may be useful in targeting cytotoxic compounds to tumor cells. We have explored their use in targeting 131-I to highly radiosensitive primitive neural tumors such as neuroblastoma and pineoblastomas. Two routes of administration have been employed, intravenous and intrathecal. Our current experience in using radiolabelled antibodies is described, indicating toxicities seen and any therapeutic benefit observed. The results of the study suggest that if targeted radiation has a role in the treatment of these malignancies, it will be restricted to the eradication of small tumor masses from the body.

Animals↗
PubMed1985

Regional ventilation in infancy. Reversal of adult pattern.

There is evidence that in infants with unilateral lung disease, oxygenation improves when the good lung is uppermost--the reverse of the situation in adults. We performed krypton-81m ventilation scanning in 18 infants and very young children (11 days to 27 months old) with and without abnormal chest radiographs. Scanning was performed with the subject supine, in the left decubitus posture (right lung uppermost), and in the right decubitus posture (right lung dependent). Fractional ventilation to the right lung fell when that lung was dependent and rose when it was uppermost (P less than 0.001). This pattern was seen regardless of the appearance of the chest radiograph. The distribution of ventilation away from dependent lung regions represents a reversal of the adult pattern, which may be due to differences between infants and adults in lung mechanics and diaphragmatic function. This study adds further weight to the argument that infants and very young children with unilateral lung disease should be positioned with their normal lung uppermost to optimize gas exchange. It also offers a rational explanation for the observation that infants with unilateral gas trapping can be successfully treated by placing them so that the diseased lung is dependent.

Age Factors↗
PubMed1985

Therapeutic application of a radiolabelled monoclonal antibody in nude mice xenografted with human neuroblastoma: tumoricidal effects and distribution studies.

Monoclonal antibody UJ13A radiolabelled with isotopes of iodine has been shown to selectively localize to human neuroblastoma xenografts. When 131I-UJ13A conjugates were given to nude mice at high doses (100-150 microCi), tumours temporarily disappeared, only to regrow. No selection for neuroblastoma cells that were UJ13A - negative was observed. Distribution studies on mice receiving radiolabelled UJ13A demonstrated the antibody is rapidly lost from the blood of animals. This cannot be accounted for by selective uptake into xenografts or any other mouse organ examined. We concluded there is a rapid equilibration of isotope between intra- and extravascular spaces in the animal. The rapid, biphasic loss of UJ13A from the blood of mice may explain why so little injected antibody can target to the human tumour xenografts.

Animals↗
PubMed1985

Reduced superovulatory response in the ewe following repeated gonadotrophin treatment.

Thirty-nine pure bred Texel ewes were superovulated with horse anterior pituitary extract (HAP) and 24 of these ewes were treated for superovulation a second time 55 to 76 days after the first treatment. A 12 day SC-9880 sponge was used to synchronise oestrus in the ewes and all were superovulated with 200 mg HAP (4 days X 50 mg HAP). Surgical insemination and cervical insemination were employed to breed the ewes following the first and second superovulation treatments, respectively. The incidence of oestrus and ewes ovulating were significantly (P less than 0.005) lower following the second treatment. There was no significant difference in the ovulation rate in ewes ovulating between the first and second treatments. The mean number of eggs recovered per ewe decreased following the second treatment but fertilisation rate was not affected. Results would suggest that the period of time between first and second superovulation treatments was not sufficiently long to allow Texel ewes to respond to a second stimulation, or that surgical insemination may have had a detrimental effect.

Animals↗
PubMed1985

Physiological variations of normal transit time in children.

Quantitation of the 99mTc-diethylenetriaminepentaacetic Acid (DTPA) scan yields by uptake analysis an estimate of individual kidney glomerular filtration rate (IKGFR) and by deconvolutional analysis an estimate of the mean transit time (MTT) of the non-reabsorbable tracer through the kidney. The whole kidney MTT is compounded of the renal parenchymal MTT and the rate of pelvic clearance; both functions are influenced by prevailing rates of salt and water excretion. The present study was undertaken to investigate the effect of physiological variations on the normal DTPA scan. The contralateral normal kidney in 11 children with suspected unilateral urinary tract obstruction were studied twice, first with an early morning scan (EMS) and second, 24 h later, following hypotonic volume expansion (HVE). A strong correlation was shown between urine osmolality and MTT. IKGFR was independent of the state of hydration, but in comparison to mild hydration, HVE shortened significantly (P less than 0.001) the normal whole kidney MTT, with less effect on parenchymal MTT (P less than 0.01) and therefore has its predominant effect on pelvic clearance. We advise caution in the interpretation of whole kidney transit time analysis without standardization of salt and water excretion rates. Parenchymal transit time offers a potentially useful clinical index.

Adolescent↗
PubMed1985

Cardiorespiratory status in relation to mild deformity in adolescent idiopathic scoliosis.

We assessed the cardiorespiratory function in young persons with adolescent idiopathic scoliosis as they entered adult life; the condition had been detected and managed through a Montreal area school screening program in the years 1975 to 1979, and all patients had been discharged with stable condition. Thirty-two youths (average age 17.7 years) with Cobb angle from 3 to 32 degrees and 93 girls (average age 17.3 years) with Cobb angle from 3 to 46 degrees did not differ from their unaffected school friends in smoking habit, respiratory symptoms, lung volumes, expiratory flow rates, diffusing capacity, maximal respiratory pressures, or submaximal exercise results. When expressed as percent predicted, pulmonary functions were within the normal range in all but one patient. Normal results were also recorded in a subsample of 20 girls undergoing a more detailed progressive maximal exercise test. This information is pertinent for counseling the adolescent with scoliosis but needs to be supplemented by prospective measurements to determine the natural history of mild scoliosis in later adult life.

Adolescent↗
PubMed1985

The relationship between renal parenchymal mass and absolute quantitation of 99Tcm-DMSA uptake. An experimental study in the growing pig.

Five Gottingen minipigs from the same litter aged 1 month entered the study and right nephrectomies were performed at staggered intervals between weeks 1 and 5. Absolute renal uptake of 99Tcm-DMSA, expressed as a percentage of the administered dose, was recorded in each animal weekly before right nephrectomy and at weekly intervals for 5 weeks post-nephrectomy. Before nephrectomy absolute renal uptake of 99Tcm-DMSA ranged between 16.8 and 21.5% (mean 18.6%) per kidney with no difference between right and left kidneys. After right nephrectomy, uptake in the left kidney approximately doubled within 1 week. No correlation was shown between renal parenchymal mass and absolute 99Tcm-DMSA uptake in paired or solitary normal kidneys undergoing growth or compensatory growth.

Animals↗