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Biomedical subjects

P M Bretland

Publications and source records attributed to P M Bretland.

14 recordsLinked to original sources
PubMed1994

Pulled elbow in childhood.

In this injury, a sudden pull on the pronated, extended arm of a child up to 5 years of age is followed by refusal to use the arm. After a simple flexion, supination and extension manoeuvre the child starts using the arm in minutes. Radiographs are said to be normal. At least 13 theories of the mechanism have been advanced. Anterior subluxation of the radial head has never been proved radiographically or experimentally. Available evidence favours momentary distraction of the radiocapitellar joint in pronation which allows upward slip of the annular ligament upon the radial head at its shortest diameter and interposition of part of the anterior capsule between the two bones. Radiography is difficult, usually producing oblique views in pronation which are not easy to interpret. The main differential diagnosis is from epiphyseal rotation. In any doubtful case early repeat radiography is essential taking matched views of both elbows, even if non-standard. A collection of 28 radiographs has been analysed, two recent typical contrasting cases are presented, two signs to identify an oblique view of a normal elbow are described and the literature is reviewed. If the best radiograph available in an injured elbow in a child is a normal oblique view in pronation, pulled elbow is a likely diagnosis.

Child, Preschool↗
PubMed1992

The single compartment model applied to the large renal pelvis: a preliminary study.

Diuresis renography should exclude or confirm pelvi-ureteric junction obstruction. Numerous equivocal cases seen here had large renal pelves with slow emptying on frusemide diuresis. An attempt was made to relate the rate of emptying to the volume of the renal pelvis. The fully distended renal pelvis during frusemide diuresis appears to satisfy the criteria of the single compartmental model which predicts a linear relationship between volume and flow rate, i.e. F = [0.693 V0]/t1/2 where F is the flow rate, V0 is the volume and t1/2 the time at which half the tracer has disappeared. Clearance half-time was measured from the diuresis renogram curve. Volume was estimated from a longitudinal ultrasound image at the end of the procedure, using a volumetric version of Simpson's rule as a sequential slice technique, given a roughly circular transverse image. Of 18 kidneys in 14 adult patients, three had large volume pelves and short emptying times. The remaining 15 showed a roughly linear relationship between volume as estimated and clearance half-time. This appears to validate both the theory and the method and permits calculation of the pelvic outflow rate. An hypothesis to explain the large unobstructed renal pelvis is advanced.

Adult↗
PubMed1990

Aspects of AIDS.

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Acquired Immunodeficiency Syndrome↗
PubMed1988

Costing imaging procedures.

The existing National Health Service financial system makes comprehensive costing of any service very difficult. A method of costing using modern commercial methods has been devised, classifying costs into variable, semi-variable and fixed and using the principle of overhead absorption for expenditure not readily allocated to individual procedures. It proved possible to establish a cost spectrum over the financial year 1984-85. The cheapest examinations were plain radiographs outside normal working hours, followed by plain radiographs, ultrasound, special procedures, fluoroscopy, nuclear medicine, angiography and angiographic interventional procedures in normal working hours. This differs from some published figures, particularly those in the Körner report. There was some overlap between fluoroscopic interventional and the cheaper nuclear medicine procedures, and between some of the more expensive nuclear medicine procedures and the cheaper angiographic ones. Only angiographic and the few more expensive nuclear medicine procedures exceed the cost of the inpatient day. The total cost of the imaging service to the district was about 4% of total hospital expenditure. It is shown that where more procedures are undertaken, the semi-variable and fixed (including capital) elements of the cost decrease (and vice versa) so that careful study is required to assess the value of proposed economies. The method is initially time-consuming and requires a computer system with 512 Kb of memory, but once the basic costing system is established in a department, detailed financial monitoring should become practicable. The necessity for a standard comprehensive costing procedure of this nature, based on sound cost accounting principles, appears inescapable, particularly in view of its potential application to management budgeting.

Capital Expenditures↗
PubMed1988

Costs of nuclear medicine.

The cost of nuclear medicine procedures in a small department run as part of a general imaging service in the financial year 1984/5, using standard commercial nomenclature and concepts (variable, semi-variable and fixed costs), are reported. The necessity for a standard costing system and the use of overhead absorption rates for all three types of cost are emphasized, and the value is shown of doing enough work to make economic use of the equipment and staff time. Nuclear medicine procedures appear to be comparable in cost to imaging procedures involving fluoroscopy.

Costs and Cost Analysis↗
PubMed1981

Urethral diverticula in the adult female.

Forty female patients with persisting urinary symptoms were investigated using positive pressure urethrography. Sixteen patients were found to have urethral diverticula; 14 of these underwent diverticulectomy. In addition, 17 patients were found to have a markedly distensible urethra on X-ray and only the remaining 7 were deemed normal. The clinical and radiological features and surgical management of these patients are presented.

Adult↗
PubMed1980

Kidney biopsy.

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Biopsy, Needle↗
PubMedDate not supplied

Complex tubular flow in the acutely obstructed kidney.

Application of Poiseuille's Law of Laminar Flow to the renal tubules using published figures for their dimensions permits estimates of the pressure differences required to produce flow through the different types of nephron and their different segments. In the obstructive situation the pressures, flows and osmolar relationships (particularly those associated with the concentration mechanism) are greatly altered. It may be predicted that this, together with a greater osmotic leak from the distal convoluted tubules of nephrons arising from peripheral glomeruli, will lead to complex (i.e. mixed forward and retrograde) flow in the respective distal convoluted and collecting tubules. Such an hypothesis would explain some hitherto ill-understood phenomena, including resorption from the obstructed renal pelvis, some aspects of ascending renal infections, reflux nephropathy and chronic obstructive disease, and certain radiological appearances in acute ureteric obstruction in man.

Absorption↗