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Biomedical subjects

I Gordon

Publications and source records attributed to I Gordon.

At least 199 records · Page 11Linked to original sources
PubMed1988

Appropriate selection of background for 99Tcm-DTPA renography.

Since 99Tcm-DTPA is diffusible and not significantly protein bound in plasma, it rapidly enters the extravascular space following injection. Therefore, during the first few minutes of the DTPA renogram, the period on which the measurements of individual kidney glomerular filtration rate and differential function are based, background activity comprises a rising extravascular signal and a falling intravascular signal. The aim of this study was to measure the ratio of these two signals in background present within the renal region of interest (ROI) and compare it with the ratio in a background ROI. An appropriate background ROI is one in which the ratio is equal to that in background in the renal ROI. To pursue this aim, we quantified the rates of change of the intravascular and extravascular activities in background and, by comparing them with the rate of increase of filtered activity, expressed them as GFR equivalents (the intravascular being negative). It is impossible, from a single renogram, to separate the rising extravascular signal from the signal due to filtered activity, and therefore impossible to quantify the extravascular GFR equivalent present in background within the renal ROI. We therefore studied six patients undergoing bone marrow transplantation before and after cyclosporin treatment. By comparing the dynamic renographic data between the two sequential studies, the substantial fall in GFR (from 107 +/- 12 S.D. to 49 +/- 7 ml min-1) permitted separate quantification of the extravascular GFR equivalent in the renal ROI in both studies. Three of the patients were studied on a third occasion after cyclosporin. In two, GFR remained low and these studies were paired with corresponding baseline studies, while in the other it increased and this was compared with the nephrotoxic study, giving a total of nine paired studies between which GFR changed. The ratio of intravascular to extravascular GFR equivalents in a background ROI placed above the kidney was considerably greater, and in a background ROI below the kidney considerably less, than that in the renal ROI. A background ROI which was the difference between the renal ROI and a perirenal ROI, 2 pixels outside the renal ROI along the horizontal and 1 pixel outside along the vertical, gave a ratio almost identical to that of the background within the renal ROI (renal ROI ratio:background ROI ratio = 1.09 +/- 0.17 S.D., n = 18).(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1988

Pelviureteric junction obstruction. The value of a post-micturition view in 99mTc DTPA diuretic renography.

Eighty-one 99mTc DTPA renograms were performed in 31 children who had previously undergone pyeloplasty for pelviureteric junction obstruction (PUJ). A post-micturition image following a diuretic stimulus excluded obstruction in 50% of the patients in whom the frusemide T75 was abnormally prolonged beyond 10 min. Evaluating the 99mTc DTPA renogram and the response to a diuretic without both changing the patient's position and ensuring an empty bladder may lead to incorrect diagnosis of PUJ obstruction.

Follow-Up Studies↗
PubMed1987

Recidivism in a cohort of young Australian drinking-drivers.

Four hundred and sixty-three men aged 18-25 years were referred to a counselling programme in 1975-1977, after their first conviction for an alcohol-related traffic offence. Records of the Victoria Police, and those of the Motor Registration Board, were searched for subsequent alcohol-related traffic offences up to February 1984. Those subjects who had left the State of Victoria or had died were identified, and a "survival" curve was constructed where survival implied freedom from reconviction for an alcohol-related traffic offence. By means of Cox's proportional hazards model, the rate ratios of a number of predictor variables of recidivism were calculated; those of significance were the number of drinks per week, social class, and a history of "family troubles with drinking". Reduction of alcohol consumption may be a more appropriate goal in programmes that are concerned with the counselling of young drinking-drivers than is attempted modification of the drinking-driving nexus.

Accidents, Traffic↗
PubMed1987

Current mortality in the Australian petroleum industry: the healthy-worker effect and the influence of life-style factors.

A surveillance system, to monitor mortality and cancer morbidity on a continuing basis, has been established in the Australian petroleum industry. A baseline survey of 11,573 employees, by personal interview, was carried out in 1981-1983. By the end of June 1986, 33,712 person-years of observation in men had accrued, with 109 deaths. Standardized mortality ratios, with the Australian national death rates as reference, indicate that in terms of mortality from all causes and in mortality from the more common diseases, the death rates in this population are substantially lower than in the national population. Standardization was also carried out in the case of employed men, with data from contributors to the Commonwealth superannuation fund as reference, in order to provide a more appropriate contrast. The risks of tobacco smoking are demonstrated, as is the probable protective effect of mild-to-moderate alcohol consumption. The advantages to the occupational physician in being able to describe current mortality patterns, and in being able to delineate "at-risk" groups are discussed, particularly in the context of health promotion and other interventions.

Alcohol Drinking↗
PubMed1987

The symptomatic hip in childhood: scintigraphic findings in the presence of a normal radiograph.

The principal causes in children of a non-acute painful hip are Perthes disease and synovitis (irritable hip). The 99mTc methylene diphosphonate (MDP) bone scan appearances in Perthes disease are well-known; in synovitis, the hip may show a diffuse increase in activity or may be normal. The significance of bone scintigraphy in the clinical setting of non-acute hip symptoms with normal skeletal radiography has been evaluated in 36 symptomatic children. The mean duration of symptoms prior to scan was 3 months (range 1 week-17 months). On the basis of final diagnosis, established by clinical findings, bone scan, X-ray and follow-up, the children were divided into two groups: synovitis or Perthes disease. Of the 33 scans in the 32 children with synovitis, 18 were normal and 15 showed diffusely increased activity on the painful side. All four patients with Perthes disease had focal femoral head abnormalities in the painful hip. Of the 18 children with normal scans, none went on to develop a skeletal disorder. In children with hip pain of over 1 week's duration, the main value of the bone scan is the early detection of Perthes disease. Diffuse increased activity on the painful side suggests synovitis. A normal scan virtually excludes significant skeletal abnormality.

Child↗
PubMed1987

Imaging the kidneys and urinary tract in the neonate with acute renal failure.

Transitional nephrology seriously affects the manner in which radiological investigations and other forms of imaging are undertaken in the neonate. When this is complicated by acute renal failure then caution must be exerted in taking care of the neonate. The use of ultrasound and micturating cystourethrography are well described and form the baseline for all imaging of the renal tract. The physiological handling of TC99m DTPA and the contrasts used for IVU are described as well as the normal appearances of these techniques in the neonate. TC99m DMSA is also included, as are other modalities of imaging.

Acute Kidney Injury↗
PubMed1987

Indications for 99mtechnetium dimercapto-succinic acid scan in children.

The 99mtechnetium dimercapto-succinic acid scan provides an image of functional renal parenchyma. This static scan has specific indications and cannot be used simply in place of a 99mtechnetium diethylenetriaminepentaacetic acid scan. The major clinical indications for this investigation are the detection and/or evaluation of a renal scar, the small or absent kidney, an occult duplex system, certain renal masses, systemic hypertension or suspected vasculitis. The physiology of the 99mtechnetium dimercapto-succinic acid scan is reviewed briefly.

Child↗
PubMed1987

Sample size estimation in occupational mortality studies with use of confidence interval theory.

In occupational epidemiology, the standardized mortality ratio is firmly entrenched as an analytic tool. Sample size determinations have usually been made in a hypothesis testing framework. However, since interval estimation is the usual goal of analysis, it may be more appropriate to use confidence interval theory to estimate the required sample size. This paper gives the method and some results for determining the required "expected number" of deaths, based on specifications concerning the confidence interval for the true standardized mortality ratio.

Epidemiologic Methods↗
PubMed1987

99mTc DTPA scanning with diuretic washout. Is it useful in the investigation of obstruction in the presence of gross renal tract dilatation?

Diuretic-enhanced 99mTc DTPA renal scanning aims to determine whether or not a kidney is obstructed. In the presence of gross renal tract dilatation the validity of this technique is questioned. Twenty-eight patients (51 kidneys) with the prune belly syndrome, characterised by gross dilatation and tortuosity of the ureters, were studied. These patients underwent diuretic 99mTc DTPA scanning at the time of diagnosis and at yearly intervals thereafter. Long-term clinical follow-up (3 years) with serial serum creatinine was available in all children. In all cases renal function remained stable and on this basis urinary tract obstruction was excluded. Analysis of the first 99mTc DTPA scan included differential function, whole kidney mean transit time (WKMTT) and the time taken for tracer activity to fall to 75% of peak activity after diuretic stimulus (T75). Using the 99mTc DTPA scan, obstruction can be excluded if the WKMTT is less than 5 min or, in the presence of a prolonged WKMTT, if the diuretic stimulus results in a T75 of less than 5 min. A T75 of between 5 and 10 min is considered equivocal and a T75 exceeding 10 min means that obstruction cannot be excluded. 99mTc DTPA scanning, using these criteria for diagnosis, provided false positive information in 22 kidneys (43%). There were no false negatives. 99mTc DTPA scanning with diuretic washout, using WKMTT and T75 criteria, is not appropriate for the detection of renal tract obstruction in the presence of marked upper renal tract dilatation, since the false positive rate of 43% is unacceptably high.

Adolescent↗