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OBJECTIVE: To demonstrate that the positive parathyroid sestamibi scan, if correctly interpreted and applied, truly represents a parathyroid adenoma, never a "false-positive" scan. SUMMARY BACKGROUND DATA: Although the sestamibi scan is widely ordered preoperatively to locate parathyroid adenomas, concern about a false-positive scan often causes surgeons to distrust the results. Tissues such as thyroid adenomas and lymph nodes have been blamed for false-positive studies, but the radioactivity of these presumed false-positive tissues has never been measured. METHODS: Over an 1 8-month period, 17 patients were referred for persistent primary hyperparathyroidism after undergoing at least one neck exploration. All patients had a sestamibi scan prior to their initial operation that was interpreted as clearly positive and then, during or after an unsuccessful operation, deemed false-positive by the surgeon. At the authors' institution, all patients underwent repeat sestamibi scintigraphy and were taken to the operating room while radioactive for a minimally invasive radioguided parathyroidectomy (MIRP). RESULTS: The authors' sestamibi scans demonstrated the same single focus of radioactivity displayed on the outside scans, clearly positive. During MIRP, an adenoma was successfully located and removed in all patients, with confirmation of the diagnosis by quantitative differential radioactivity and subsequent histologic examination. Removal of the radioactive tissue cured all patients. CONCLUSION: Intraoperative nuclear mapping permitted identification and removal of parathyroid adenomas in all patients with positive sestamibi scans that had previously been labelled false-positive, indicating that each patient would have been cured during their previous operation if radioguided techniques were used. Surgeons should be extremely cautious in deciding intraoperatively that a positive sestamibi scan is a false-positive scan.

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PURPOSE: We evaluated the difference in response patterns of captopril versus standard renography for assessing hydronephrosis due to suspected ureteropelvic and ureterovesical junction obstruction. This technique may identify hydronephrotic kidneys in which normal function is maintained by vasoactive compensatory mechanisms. Sustained obstruction may cause these mechanisms to fail, and expose the kidneys to permanent functional deterioration in the long term. MATERIAL AND METHODS: We prospectively studied 15 boys and 8 girls with a mean age of 3.5 years with grades III to IV/IV hydronephrosis. Evaluations included renal sonography, standard diuretic and captopril renography, glomerular filtration rate, voiding cystography, serum creatinine, blood pressure, and urinalysis with culture and sensitivity. Obstruction was suspected at the ureteropelvic junction in 19 kidneys and at the ureterovesical junction in 9. We compared differential function values obtained by standard diuretic and captopril renography. RESULTS: We observed certain patterns in response to captopril renography, including pattern 1--unilateral decrease in hydronephrotic kidney relative function in 5 of 23 cases, 2--bilateral decreased function in 2, 3--bilateral increased function in 4 and 4--no change in function in 12 on standard renography. When half-time was more than 20 minutes on standard diuretic renography in 8 cases, captopril renography showed an ipsilateral decrease and bilateral increase in glomerular filtration rate in 4 and 1, respectively, and no change in 3. In 12 of the 23 patients (52%) there was no difference in the results of captopril and diuretic renography as well as no change in differential function on standard diuretic renography during 1 1/2 years of observation. Surgical correction was performed in 4 patients in whom half-time was greater than 20 minutes and differential function was decreased on captopril renography. CONCLUSIONS: Our preliminary study reveals that there may be a role for captopril renography for detecting renin-angiotensin system mediated compensatory mechanisms in obstructive uropathy. When such compensatory mechanisms are activated, they may be unmasked by captopril, producing 1 of 4 patterns on renography and glomerular filtration rate. Patterns may indicate different degrees of impending renal function impairment and, thus, they may become useful for determining the progression of injury, when present, and the appropriate timing of surgical intervention.

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Primarily because of the lack of highly accurate preoperative localizing studies, the standard operation for primary hyperparathyroidism (HPTH) has consisted of bilateral neck exploration with examination of all four parathyroid glands. Recent experience with the technetium-99m-Sestamibi scan at our hospital has suggested that this single test was now accurate enough to allow unilateral neck exploration. This study was designed to examine the efficacy and safety of minimally invasive parathyroid-ectomy in select patients with a single adenoma demonstrated on a preoperative sestamibi. Eighteen consecutive patients with primary HPTH in whom a sestamibi scan suggested a single adenoma underwent unilateral neck exploration through a 2.5-cm incision, which was extended as necessary. Results were compared to the preceding 25 parathyroid explorations for primary HPTH due to a single adenoma, which were nondirected and included bilateral neck exploration. All patients undergoing minimal exploration were found to have a single adenoma and demonstrated a normal serum calcium within 24 hours of surgery. Standard bilateral exploration failed to locate the adenoma in one patient requiring subsequent re-exploration. Operative time, incision length, and length of hospital stay were all significantly less for those undergoing minimal exploration (all P < 0.01). There were no complications in either group. Minimally invasive neck exploration is a safe and effective treatment for primary HPTH, is easily accomplished under local anesthesia, and is associated with significant reductions in operative time and hospital stay. Limited exploration provides a better cosmetic result while decreasing the potential complications of bilateral exploration, but is dependent upon a high-quality sestamibi scan.

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BACKGROUND: The inability to predict the location and number of diseased parathyroid glands has precluded the wide acceptance of unilateral neck exploration for primary hyperparathyroidism. We used intraoperative nuclear mapping in patients identified by sestamibi scanning to have a single adenoma in hopes of minimizing operative intervention while maintaining the efficacy of a full exploration. METHODS: Fifteen consecutive patients with primary hyperparathyroidism underwent technetium 99m-labeled sestamibi scanning 3.0 +/- 0.1 hours before operation. Placement of the initial 2.0 cm incision and all dissection were guided by quantitative gamma counting in four neck quadrants with an 11 mm Neoprobe. Ex vivo radioactivity was determined for parathyroid glands, fat, and lymph nodes. Potential radiation hazards were assessed. RESULTS: Intraoperative nuclear mapping discriminated between 14 solitary adenomas and one patient with four-gland hyperplasia that was not predicted on preoperative sestamibi scanning. Removal of the adenoma resulted in a decline in radioactivity in that quadrant (p < 0.001) and the entire neck (p < 0.05), with equalization of all neck quadrants. Ex vivo counts always identified parathyroid tissue (p < 0.0001 versus fat and lymph node). Adenomas were located in 19 +/- 1.7 minutes through a 2.3 +/- 0.1 cm incision. No significant radiation hazard existed, and no special handling of the specimen was required (0.06 +/- 0.01 mR/hr). CONCLUSIONS: Intraoperative nuclear mapping complements sestamibi scanning to help distinguish single-gland from multigland disease. This technique allows for a minimally invasive operation under local anesthesia in a true outpatient setting.

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Microleakage contributes to deterioration of materials, recurrent decay, growth of microorganisms at the interface, and postoperative tooth sensitivity. This study examined the microleakage between amalgams and tooth surfaces with a cavity liner, a 4-methacryloxyethyl trimellitate anhydride bonding agent (Amalgambond) and six different types of amalgams. Class 1 cavity preparations in extracted human molars were filled with different combinations of liners and amalgams and were stored at 37 degrees C in physiologic saline solution. After 1 week half of each amalgam restoration was removed. Within the same group the same cavity treatment was performed and the same type of amalgam was packed as before. Microleakage was determined after 2000 thermal cycles. Statistical analysis indicated that Amalgambond significantly reduced microleakage of different amalgams compared with the Copalite-lined and unlined controls. No microleakage was detected at the interface between the existing and replacement amalgams.

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Sodium pertechnetate Tc99m scintigraphy is a valuable technique for the evaluation of acute testicular torsion in postpubescent males. However, in neonates and children with small testicles, the method is less reliable. Since the testicles of adult rats and young children are of similar size, the reliability of testicular imaging for detecting torsion was evaluated in this species. The utility of the radionuclide angiogram (RA) and static images were determined in 17 anesthetized animals before, 2 h after and 20 h after ligation of the left spermatic cord. The preligation RA was asymmetric in 27% of animals, while the static images were abnormal in 18%. Postligation flow and static images were abnormal in 57% and 82% of the animals (localized to the correct side, 38% and 36%), respectively. The animals with vascular occlusion failed to show any statistically significant greater incidence of decreased radionuclide accumulation on the ligated side. To determine the influence of relative perfusion and extracellular fluid space of the scrotum and testicles on the images, additional studies were performed with 201Tl (representing perfusion) and 99mTcO4- (representing ECF space). Perfusion was approximately equal in the testis and epididymis but significantly higher in the scrotum. These results suggest that scrotal scintigraphy is unreliable for detecting acute torsion of small testicles.

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Two years of giant star grass, Cynodon nlemluensis var. nlemfuensis, in a field plot markedly reduced the incidence of the root-knot nematodes. Tomato planted following the grass showed very little or no root galling and the yield was thrice that of tomato planted on an adjacent field plot previously cropped to tomato. Replicated greenhouse experiments indicated that six varieties of Cynodon were resistant to root-knot nematode but it took up to 6 months of grass growth to appreciably lower the nematode population. The nematodes were eliminated from the soil by all the six grass varieties after 18 months.