Potential interference of agents on radioiodide thyroid uptake in the euthyroid rat.

The objective of this research was to investigate the merits of controlled studies with euthyroid rats as a means of determining the influence of dose and time after administration of agents that may interfere with radioiodide uptake in the thyroid. METHODS: Potassium iodide (KI), propylthiouracil (PTU), diatrizoate meglumine, and iohexol were selected to represent interfering agents. Two dose levels per agent were investigated. Doses used were 1 and 2 mg/kg of body weight for KI, 3.5 and 7 mg/kg of body weight for PTU, 1 mL/kg (282 mg I/kg) and 2 mL/kg (564 mg I/kg) of body weight for diatrizoate meglumine, and 1 mL/kg (300 mg I/kg) and 2 mL/kg (600 mg I/kg) of body weight for iohexol. The 24-h radioiodide thyroid uptake was determined after (131)I was given at 1, 8, 15, and 22 d after administration of interfering agents. RESULTS: The percentage radioiodide uptake value for the thyroid decreased significantly compared with controls for all agents and both doses on day 1 but returned to control levels by day 22 for all agents and both doses The time to return to normal varied between agents and doses. CONCLUSION: We conclude that the interfering agent, the dose given, and the length of time after administration influence the potential for an agent to affect radioiodide uptake in the thyroid. Further studies with the rat, preferably hyperthyroid, would be beneficial in generating data to reduce confusing contradictory information on the length and severity of interference of agents in radioiodide thyroid studies.     

Changes in bladder function following a surgical alteration in outflow resistance

The changes in bladder function occurring after a surgical alteration in bladder outflow resistance were studied in 20 males undergoing transurethral prostatectomy (TURP) and in 20 females undergoing an endoscopic bladder neck suspension (EBNS). Serial cystometrograms (CMG) were performed before operation, and on alternate days after spontaneous micturition was re-established, for 5 days in the males and for 21 days in the females. CMGs were repeated at 3 months and 1 year after operation. After TURP voiding pressures (P_det) fell rapidly from a mean of 118 cm H₂O before operation to 57 cm H₂O at 5 days, with an increase in flow rate during this time from 10.5 ml/s to 24 ml/s. Detrusor instability that had been present in 14 patients resolved within 2 days in 12. There was no further significant urodynamic change over the 1-year study period. After EBNS, there was an early rise in voiding pressure (P_det rose from 26 cm H₂O before operation to 42 cm H₂O at 3 days). This continued to increase up to 21 days particularly in those patients with initial large residuals. Three patients developed detrusor instability. Flow rates were greatly reduced at first (27 ml/s before operation and 13 ml/s at 3 days), and gradually increased in line with voiding pressures, yet were still diminished 1 year after operation. The urodynamic changes following a reduction in bladder outflow resistance by TURP are immediate and sustained and unlikely to be the result of structural changes within the bladder wall. EBNS produces an increase in outflow resistance and it can be several weeks before balanced voiding is achieved, with significantly increased detrusor pressures needed to achieve complete bladder emptying at a reduced flow rate.     

Dipyridamole technetium 99m sestamibi myocardial tomography as an independent predictor of cardiac event-free survival after acute ischemic events

Background  

A total of 137 consecutive patients with recent uncomplicated myocardial infarction (n=31) or unstable angina (n=106) were studied to determine the relative prognostic value of predischarge clinical risk stratification and intravenous dipyridamole stress sestamibi (MIBI) myocardial tomography in patients unable to exercise maximally after an acute ischemic coronary event.     

Mitral balloon valvuloplasty for patients aged over 70 years: an alternative to surgical treatment

We report the results and one-year follow-up of 20 elderly patients (age range 70-82 years) with severe rheumatic mitral stenosis treated by mitral balloon valvuloplasty (MBV). All 20 were breathless at rest despite treatment with diuretics and digoxin. At cardiac catheterization, successful dilatation was achieved in 17 patients: mean transvalvular mitral gradient fell by 45%, mean cardiac output rose by 24% and mean valve area increased by 76%. There was no procedure-related mortality. At one month, 15 patients had experienced an improvement in symptoms of at least one New York Heart Association class and, at one year, ten had maintained this improvement. Three patients proceeded to mitral valve replacement because of a suboptimal symptomatic result. Mitral balloon valvuloplasty can be successfully performed with significant symptomatic benefit in frail elderly patients unfit for surgery and may also be offered to other selected elderly patients as an alternative to surgical treatment.     

The magnetic resonance appearances of the normal thymus in children.

The normal thymus in children is highly variable in size and shape. In some cases this has led to the misdiagnosis of mediastinal pathology and an unnecessary thoracotomy. Twenty-five children without suspicion of mediastinal pathology and five children with suspected mediastinal pathology were imaged using magnetic resonance imaging (MRI). MRI is recommended to distinguish between the normal and abnormal thymus in difficult cases where other imaging techniques are inconclusive.