PubMed · 5538729
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R E Fechner, M J Horwitz. 1971. Pathologic quiz case 1.. https://pubmed.ncbi.nlm.nih.gov/5538729/
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An 8-year-old stallion was evaluated because of recurrent urinary tract infections and chronic intermittent urospermia. After extensive diagnostic testing, it was hypothesized that the stallion had a reflex dyssynergia of the bladder and urethral sphincter. Initial attempts to manage the urospermia included semen fractionation, semen collection after voluntary urination, and use of semen extenders. None of these efforts reliably yielded a quality ejaculate. Administration of imipramine hydrochloride (1.2 mg/kg of body weight, PO, 4 hours prior to semen collection) was initiated in an attempt to enhance bladder neck closure during ejaculation. This treatment, combined with voluntary urination prior to ejaculation, resulted in ejaculates containing little or no urine. Using this protocol, 19 of 20 mares bred during the subsequent 2 years became pregnant. By the third year, the bladder dysfunction had progressed, and the urospermia was no longer manageable. Bladder catheterization, followed by manual expression of the bladder per rectum, were necessary prior to each semen collection to obtain a urine-free ejaculate. Three-and-a-half years after initial examination, transitional cell carcinoma of the bladder with metastasis was identified, and the stallion was euthanatized. It is not known whether the transitional cell carcinoma was related to the dysfunctional bladder. Imipramine hydrochloride did not eliminate, but did reduce, the frequency and degree of urospermia in the affected stallion for approximately 2 years.
PURPOSE: The efficiency of four fast simulated annealing algorithms for optimizing conformal radiation therapy treatment plans was studied and the resulting plans were compared with each other and to optimized conventional plans. METHODS AND MATERIALS: Four algorithms were selected on the basis of their reported successes in solving other minimization problems: fast simulated annealing with a Cauchy generating function, fast simulated annealing with a Lorentzian generating function, variable step size generalized simulated annealing (VSGSA), and very fast simulated reannealing (VFSR). They were tested on six clinical cases using a multiple beam coplanar conformal treatment technique. Relative beam weights were computed that maximized the minimum tumor dose subject to dose-volume constraints on normal organ doses. Following some initial tuning of the annealing parameters, each algorithm was applied identically to each test case. Optimization tests were run using different random number sequences and different numbers of iterations. RESULTS: The VSGSA algorithm consistently produced the best results. Using long run times, it generated plans with the highest minimum tumor dose in five of the six cases. For the short run times, the VSGSA solutions averaged larger minimum tumor doses than those of the other algorithms for all six patients, with increases ranging from 0.4 to 5.9 Gy. For three of the patients, the conformal plan gave a clinically significant increase in the minimum tumor dose over the conventional plan, ranging from 8.2 to 13.0 Gy. In two other cases, there was little difference between the two treatment approaches. For one case, the optimized conventional plan was much better than the conformal plan because the conventional beam arrangement included wedges, which offset the multiple beam advantage of the conformal plans. CONCLUSIONS: For equal computing times of both long and short duration, the VSGSA algorithm consistently produced conformal plans that were superior to those produced by the other algorithms. The simple conformal technique used in this study showed a significant potential advantage in the treatment of abdominal tumors. In three of the cases, the conformal plans showed clinically important increases in tumor dose over optimized conventional plans.
PURPOSE: To assess the feasibility of accelerated hyperfractionated radiotherapy in the treatment of breast, abdominal cavity, and pelvic tumors. METHODS AND MATERIALS: Between August 1989 and March 1993, 39 patients were treated in Portsmouth by an accelerated, hyperfractionated regimen giving 45 to 54 Gy three times a day over 12 days. Twenty patients had abdominal cavity or pelvic tumors and 19 patients breast carcinoma, 9 of whom were treated prophylactically after local excision. RESULTS: No local recurrence has been observed in the 19 patients with breast carcinoma, and out of the 20 with abdominal or pelvic tumors, 6 showed complete regression and so far no severe late damage has been observed. In those patients who had pelvic or abdominal tumors treated, the acute toxicity varied widely from minimal to very intensive. No surgical intervention was necessary and most reactions settled within a 6-week period. CONCLUSION: Accelerated fractionation by small increments is well tolerated by the breast, pelvic, and abdominal organs.