Biomedical subjects
Publications and source records attributed to G M Preminger.
We describe a case of direct percutaneous ureterolithotomy in which the combination of antegrade control, a ureteral stent and precise fluoroscopic imaging resulted in a successful outcome. This technique may be helpful when other more traditional methods for percutaneous ureteral stone removal fail.
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Anti-factor VIII antibodies, inherited or acquired inhibitors of the factor VIII molecule, have not been reported previously in the urological literature. Although more common in hemophiliac patients who have received multiple transfusions, this anticoagulant may be the cause of severe hemorrhage in nonhemophiliac patients. We describe a patient with carcinoma of the prostate and an unsuspected anti-factor VIII antibody, who experienced excessive postoperative bleeding and prolonged hospitalization following a vesicolithotomy and bilateral orchiectomy. A prolonged partial thromboplastin time and a significant decrease in measurable factor VIII clotting activity in a patient with no history of bleeding problems are essential clues in making the diagnosis of a factor VIII inhibitor. This coagulation defect is treated best with prothrombin complex concentrates, which contain vitamin K dependent clotting factors.
Acute urinary retention in female patients often is attributed to psychogenic disturbances. However, it is apparent that this problem may be the harbinger of significant organic illness. Our experience with 27 patients reveals that careful evaluation and appropriate treatment prevent further urological complications and aid in the diagnosis of underlying pathological conditions.
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Previous experimental investigations of embryonic kidney development with in vitro organ culture techniques have been limited by the short duration of explant viability. Utilization of chick chorioallantoic membranes for transplanting undifferentiated murine kidney rudiments has allowed vascularization of the grafts with advanced maturation and the appearance of early nephron units.
Previous experimental investigations of embryonic kidney development with in vitro organ-culture techniques have been limited by the short duration of graft viability and lack of detailed anatomic development. In a modified application of the chick chorioallantoic-membrane (CAM) grafting technique, we have transplanted 11-day-old undifferentiated embryonic murine kidney rudiments and studied their differentiation and early morphogenesis. Surviving grafts, maintained for 5-10 days on the CAM, demonstrated well-developed convoluted secretory tubules and highly branched collecting ducts. Definitive glomeruli were also identified in these grafts by the presence of efferent tubules, visceral and parietal epithelium, capillary tuft, and Bowman's space. In vitro branching of the ureteric bud preceded formation of definitive tubules. Sections of the CAM grafts appeared histologically comparable to the 14-15-day in vivo embryonic metanephros. Grafts of 10-day-old rudiments showed minimal kidney development; fewer grafts survived, fewer tubules were formed, and fewer glomeruli developed. Our results indicate that the CAM is an efficient site for in vitro murine kidney development with both vascularization of the explant and extensive maturation, including the appearance of primitive nephron units.
PURPOSE: The purpose of this study was to analyze interobserver agreement in the interpretation of unenhanced helical CT (UHCT) for the evaluation of ureteral stone disease and obstruction. METHOD: One hundred three UHCT examinations were independently and retrospectively reviewed by five readers including attending radiologists, a radiology resident, and an attending urologist. Examinations were interpreted as positive, negative, or indeterminate for ureteral stone disease and obstruction. The Cohen kappa test was used to measure interobserver agreement. The accuracy of the readers was also assessed. RESULTS: The kappa value ranged from 0.67 to 0.71 among the three attending radiologists and from 0.65 to 0.67 among the radiology attending physicians and radiology resident. Although the urologist tended to agree less well with the other readers (kappa range: 0.33-0.46), there was no statistically significant difference (p < 0.05) in the accuracy among all five readers. The percentage of cases interpreted as indeterminate ranged from 8 to 25% and almost invariably involved difficulty distinguishing phleboliths from minimally obstructing distal ureteral calculi. The percentage of UHCT scans correctly interpreted as positive and correctly interpreted as negative ranged from 73% (n = 27) to 86% (n = 32) and 63% (n = 22) to 86% (n = 30), respectively. CONCLUSION: Interobserver agreement was very good among the radiology attending physicians and resident and moderate with the urologist. The examination is an accurate technique in the evaluation of ureteral stone disease, although limitations exist, particularly in the diagnosis of minimally obstructing distal ureteral calculi.
To evaluate the impact of the percutaneous removal of renal calculi we compared 41 patients who had undergone open renal surgery to 88 patients who had a one- or two-stage percutaneous nephrostolithotomy for symptomatic urolithiasis. The two groups were similar with regard to stone size, stone location, treatment success, and complication rates. However, for patients with calculi 2.5 cm or smaller in diameter, the percutaneous procedure resulted in lower postoperative morbidity, more rapid convalescence, less hospital cost, and greater patient satisfaction. For patients with calculi larger than 2.5 cm in diameter, the percutaneous approach was slightly more expensive than open surgery but resulted in a markedly shortened convalescent period. In our experience, percutaneous nephrostolithotomy performed in a single stage under assisted local anesthesia was the most efficacious and least expensive of the percutaneous approaches.